Bind 9
Monthly
DNSSEC validation bypass in ISC BIND 9 resolvers (9.11.0 through 9.21.23 and S-editions) allows an attacker controlling a signed zone to inject validly-signed NSEC records whose 'Next Domain Name' field points outside the signer's own zone, letting forged proofs of non-existence be applied to names the zone was never authorized to speak for. Because BIND fails to enforce that the NSEC chain stays within the signer's authority, an attacker can assert that arbitrary names in other zones do not exist, poisoning resolver behavior across zone boundaries (CVSS 8.6, Scope:Changed, integrity impact). There is no public exploit identified at time of analysis and the issue is not in CISA KEV.
Remote denial of service in ISC BIND 9 lets an attacker crash a validating resolver via a maliciously crafted DNSSEC proof. When a provably-insecure delegation is covered by both NSEC and NSEC3 records at the parent but only one of those types carries an RRSIG, BIND hits a reachable assertion (CWE-617) and terminates while validating the insecurity proof. No public exploit is identified at time of analysis and it is not listed in CISA KEV, but the network-reachable, unauthenticated attack surface and named process termination make this a high-availability-impact issue for recursive resolvers.
Remote denial of service in ISC BIND 9 lets an off-path attacker crash a recursive resolver by controlling the timing and content of authoritative responses to paired queries. When a client asks named to resolve a DNAME plus an A record beneath it (or a CNAME plus an A record for the same name) and the attacker-controlled authoritative server answers the A query positively but delays the DNAME/CNAME response before returning a negative or self-referential answer, named hits a fatal assertion and terminates. The flaw is unauthenticated and network-reachable (CVSS 7.5, availability-only); there is no public exploit identified at time of analysis and it is not on CISA KEV.
Cache poisoning in ISC BIND 9 recursive resolvers allows an attacker who controls an authoritative zone to inject forged records by returning an RRSIG with fewer labels than its containing zone, tricking `named` into synthesizing a wildcard name for a zone shorter than the attacker's own. Affected versions span the 9.11.x through 9.21.x branches (including -S subscription editions), and the flaw is exploitable against default deployments because the triggering feature `synth-from-dnssec` is enabled by default. No public exploit identified at time of analysis; the issue was reported by ISC and vendor patches (9.20.26, 9.21.24) are available.
Denial of service in ISC BIND 9 lets a remote unauthenticated attacker exhaust resolver memory by flooding a DNSSEC-validating resolver with random-subdomain ('water torture') queries against a DNSSEC-signed zone. When queries arrive faster than the resolver can complete validation, memory consumption grows unbounded - orders of magnitude beyond the configured max-cache-size - eventually crashing the service. Affects a broad span of 9.11 through 9.21 release and supported-preview (-S) branches; no public exploit identified at time of analysis and it is not listed in CISA KEV.
Denial of service in ISC BIND 9 resolvers (9.20.0-9.20.24, 9.21.0-9.21.23, and 9.20.9-S1-9.20.24-S1) lets remote unauthenticated attackers exhaust CPU by luring a validating resolver to query an authoritative zone that returns many valid-but-superfluous RRSIG records, which BIND always validates even when unnecessary. The CVSS 7.5 vector (AV:N/AC:L/PR:N/UI:N/A:H) reflects an availability-only impact with no confidentiality or integrity loss. There is no public exploit identified at time of analysis and it is not in CISA KEV, but ISC has released fixed builds (9.20.26 and 9.21.24).
RPZ policy bypass and remote denial-of-service in ISC BIND 9 resolvers lets unauthenticated attackers defeat Response Policy Zone protections or crash the daemon by sending queries with names long enough to trigger a NAMETOOLONG condition during RPZ processing. Affected are BIND 9.16.0-9.18.50, 9.20.0-9.20.24, 9.21.0-9.21.23 and the corresponding -S (subscription) editions, but only where RPZ is configured with wildcard CNAME policies. No public exploit identified at time of analysis; the vendor (ISC) has released fixed builds 9.20.26 and 9.21.24.
Remote denial of service in ISC BIND 9 named allows unauthenticated attackers to trigger assertion failures and crash the resolver by sending DNS messages with non-Internet classes (CHAOS, HESIOD) or meta-classes (ANY, NONE) through code paths involving recursion, dynamic UPDATE, NOTIFY, or IN-specific record processing in non-IN data. The flaw affects BIND 9.11.0 through 9.21.21 across both open-source and Supported Preview (S1) branches, with no public exploit identified at time of analysis. CVSS 7.5 reflects high availability impact with network-reachable, low-complexity, unauthenticated exploitation.
Memory corruption in ISC BIND 9's DNS-over-HTTPS (DoH) implementation lets remote attackers trigger a use-after-free (CWE-416) by interacting with the DoH endpoint, affecting BIND 9.20.0-9.20.22, 9.21.0-9.21.21, and the 9.20.9-S1-9.20.22-S1 subscription builds; the older 9.18.x branch is explicitly not affected. The vendor scores it CVSS 9.8 (AV:N/AC:L/PR:N/UI:N), implying unauthenticated remote impact, though CISA's SSVC rates technical impact as only 'partial' and exploitation as 'none'. There is no public exploit identified at time of analysis and EPSS is very low (0.02%, 7th percentile), indicating no observed exploitation activity.
Denial of service in ISC BIND 9 DNS servers configured with TKEY GSS-API authentication allows remote unauthenticated attackers to trigger excessive memory consumption by sending maliciously crafted packets. The flaw primarily impacts Active Directory-integrated DNS and Kerberos-secured DNS deployments, where service exhaustion can disrupt authentication, name resolution, and dependent enterprise services. There is no public exploit identified at time of analysis and the issue is not listed in CISA KEV, but the CVSS 7.5 score and network-reachable, unauthenticated nature warrant timely patching.
Memory exhaustion in BIND 9 resolver allows unauthenticated remote attackers to cause denial of service by querying specially crafted domains, affecting versions 9.20.0-9.20.20, 9.21.0-9.21.19, and 9.20.9-S1-9.20.20-S1. The vulnerability stems from improper memory management (CWE-772) and can be triggered without authentication or user interaction. Patches are available for affected Ubuntu, SUSE, and Debian systems.
BIND resolver servers performing DNSSEC validation can be forced into excessive CPU consumption when encountering a maliciously crafted DNS zone, resulting in denial of service. The vulnerability affects BIND 9 versions from 9.11.0 through current versions across multiple branches (9.16.50, 9.18.46, 9.20.20, 9.21.19) including BIND Supported Preview Edition variants. The CVSS score of 7.5 indicates high availability impact with network-based exploitation requiring no authentication, though no active exploitation (KEV) or proof-of-concept availability has been indicated in the provided data.
Availability loss in ISC BIND 9 DNS server arises when a stored DNS key record containing the PRIVATEDNS algorithm (algorithm number 253) carries a malformed identifier length field that exceeds the actual identifier data. BIND accepts the structurally invalid record without rejecting it at ingestion time, but when it subsequently attempts to render that record to text - during logging, zone display, or similar operations - the inconsistent length triggers a reachable assertion (CWE-617) that causes BIND to abort and exit. No active exploitation has been confirmed (not listed in CISA KEV) and no public exploit code has been identified at time of analysis; however, BIND 9 spans a very wide version range and is critical infrastructure, making patch urgency high despite the medium CVSS score of 6.5.
DNSSEC integrity bypass in ISC BIND 9 enables network-positioned attackers to forge authenticated NXDOMAIN responses by exploiting improper validation of NSEC3 records originating from child zones. Affected are BIND 9 versions across the 9.18, 9.20, and 9.21 branches, as well as the BIND 9 Supported Preview Edition (S-series). Because the CVSS vector carries S:C (scope changed), the integrity impact propagates beyond the resolver itself to any DNS client trusting BIND's DNSSEC-validated answers. No public exploit code has been identified and the vulnerability is not listed in the CISA KEV catalog at time of analysis.
Resource exhaustion in ISC BIND 9's resolver state machine allows remote unauthenticated attackers to trigger an unbounded resend loop by sending crafted DNS queries that activate bad-server retry conditions, degrading resolver availability. Multiple active release branches are affected across standard and Subscription Edition builds spanning versions 9.18.36 through 9.21.21. No public exploit has been identified and the vulnerability is not listed in CISA KEV; however, the fully network-accessible, zero-authentication attack vector makes every exposed BIND 9 resolver a potential target.
Denial of service in ISC BIND 9 resolvers can be triggered when a SIG(0)-signed DNS message is dropped under recursive-clients pressure, creating a race that leads to a use-after-free on the discarded message buffer. Affects BIND 9.20.0-9.20.22, 9.21.0-9.21.21, and the 9.20.9-S1-9.20.22-S1 subscription branch; no public exploit identified at time of analysis and the issue is not on CISA KEV.
Amplified resource exhaustion in ISC BIND 9 resolvers enables remote unauthenticated attackers to cause disproportionate resource consumption by directing a victim resolver to query a specially crafted authoritative DNS zone. All major BIND 9 resolver branches are affected, spanning versions 9.11.x through 9.21.x including BIND 9 Supported (S1) variants, representing a broad deployment footprint across enterprise and ISP resolver infrastructure. No public exploit has been identified at time of analysis and the vulnerability is not listed in CISA KEV; ISC has released patched versions.
A use-after-return vulnerability in ISC BIND 9's SIG(0) DNS query handler allows an attacker with low-level authentication privileges to manipulate ACL matching logic, potentially bypassing default-allow access controls and gaining unauthorized access to DNS services. The vulnerability affects BIND 9 versions 9.20.0-9.20.20, 9.21.0-9.21.19, and their security branches (9.20.9-S1-9.20.20-S1), while older stable releases (9.18.x) are unaffected. Vendor patches are available, and the moderate CVSS 5.4 score reflects limited technical impact when ACLs are properly configured with fail-secure defaults.
BIND 9 DNS server crashes when processing specially crafted TSIG-authenticated queries containing TKEY records, affecting versions 9.20.0-9.20.20, 9.21.0-9.21.19, and 9.20.9-S1-9.20.20-S1 on Ubuntu, SUSE, and Debian systems. An authenticated attacker with a valid TSIG key can trigger a denial of service by sending a malformed query, disrupting DNS resolution services. A patch is available for affected installations.
DNSSEC validation bypass in ISC BIND 9 resolvers (9.11.0 through 9.21.23 and S-editions) allows an attacker controlling a signed zone to inject validly-signed NSEC records whose 'Next Domain Name' field points outside the signer's own zone, letting forged proofs of non-existence be applied to names the zone was never authorized to speak for. Because BIND fails to enforce that the NSEC chain stays within the signer's authority, an attacker can assert that arbitrary names in other zones do not exist, poisoning resolver behavior across zone boundaries (CVSS 8.6, Scope:Changed, integrity impact). There is no public exploit identified at time of analysis and the issue is not in CISA KEV.
Remote denial of service in ISC BIND 9 lets an attacker crash a validating resolver via a maliciously crafted DNSSEC proof. When a provably-insecure delegation is covered by both NSEC and NSEC3 records at the parent but only one of those types carries an RRSIG, BIND hits a reachable assertion (CWE-617) and terminates while validating the insecurity proof. No public exploit is identified at time of analysis and it is not listed in CISA KEV, but the network-reachable, unauthenticated attack surface and named process termination make this a high-availability-impact issue for recursive resolvers.
Remote denial of service in ISC BIND 9 lets an off-path attacker crash a recursive resolver by controlling the timing and content of authoritative responses to paired queries. When a client asks named to resolve a DNAME plus an A record beneath it (or a CNAME plus an A record for the same name) and the attacker-controlled authoritative server answers the A query positively but delays the DNAME/CNAME response before returning a negative or self-referential answer, named hits a fatal assertion and terminates. The flaw is unauthenticated and network-reachable (CVSS 7.5, availability-only); there is no public exploit identified at time of analysis and it is not on CISA KEV.
Cache poisoning in ISC BIND 9 recursive resolvers allows an attacker who controls an authoritative zone to inject forged records by returning an RRSIG with fewer labels than its containing zone, tricking `named` into synthesizing a wildcard name for a zone shorter than the attacker's own. Affected versions span the 9.11.x through 9.21.x branches (including -S subscription editions), and the flaw is exploitable against default deployments because the triggering feature `synth-from-dnssec` is enabled by default. No public exploit identified at time of analysis; the issue was reported by ISC and vendor patches (9.20.26, 9.21.24) are available.
Denial of service in ISC BIND 9 lets a remote unauthenticated attacker exhaust resolver memory by flooding a DNSSEC-validating resolver with random-subdomain ('water torture') queries against a DNSSEC-signed zone. When queries arrive faster than the resolver can complete validation, memory consumption grows unbounded - orders of magnitude beyond the configured max-cache-size - eventually crashing the service. Affects a broad span of 9.11 through 9.21 release and supported-preview (-S) branches; no public exploit identified at time of analysis and it is not listed in CISA KEV.
Denial of service in ISC BIND 9 resolvers (9.20.0-9.20.24, 9.21.0-9.21.23, and 9.20.9-S1-9.20.24-S1) lets remote unauthenticated attackers exhaust CPU by luring a validating resolver to query an authoritative zone that returns many valid-but-superfluous RRSIG records, which BIND always validates even when unnecessary. The CVSS 7.5 vector (AV:N/AC:L/PR:N/UI:N/A:H) reflects an availability-only impact with no confidentiality or integrity loss. There is no public exploit identified at time of analysis and it is not in CISA KEV, but ISC has released fixed builds (9.20.26 and 9.21.24).
RPZ policy bypass and remote denial-of-service in ISC BIND 9 resolvers lets unauthenticated attackers defeat Response Policy Zone protections or crash the daemon by sending queries with names long enough to trigger a NAMETOOLONG condition during RPZ processing. Affected are BIND 9.16.0-9.18.50, 9.20.0-9.20.24, 9.21.0-9.21.23 and the corresponding -S (subscription) editions, but only where RPZ is configured with wildcard CNAME policies. No public exploit identified at time of analysis; the vendor (ISC) has released fixed builds 9.20.26 and 9.21.24.
Remote denial of service in ISC BIND 9 named allows unauthenticated attackers to trigger assertion failures and crash the resolver by sending DNS messages with non-Internet classes (CHAOS, HESIOD) or meta-classes (ANY, NONE) through code paths involving recursion, dynamic UPDATE, NOTIFY, or IN-specific record processing in non-IN data. The flaw affects BIND 9.11.0 through 9.21.21 across both open-source and Supported Preview (S1) branches, with no public exploit identified at time of analysis. CVSS 7.5 reflects high availability impact with network-reachable, low-complexity, unauthenticated exploitation.
Memory corruption in ISC BIND 9's DNS-over-HTTPS (DoH) implementation lets remote attackers trigger a use-after-free (CWE-416) by interacting with the DoH endpoint, affecting BIND 9.20.0-9.20.22, 9.21.0-9.21.21, and the 9.20.9-S1-9.20.22-S1 subscription builds; the older 9.18.x branch is explicitly not affected. The vendor scores it CVSS 9.8 (AV:N/AC:L/PR:N/UI:N), implying unauthenticated remote impact, though CISA's SSVC rates technical impact as only 'partial' and exploitation as 'none'. There is no public exploit identified at time of analysis and EPSS is very low (0.02%, 7th percentile), indicating no observed exploitation activity.
Denial of service in ISC BIND 9 DNS servers configured with TKEY GSS-API authentication allows remote unauthenticated attackers to trigger excessive memory consumption by sending maliciously crafted packets. The flaw primarily impacts Active Directory-integrated DNS and Kerberos-secured DNS deployments, where service exhaustion can disrupt authentication, name resolution, and dependent enterprise services. There is no public exploit identified at time of analysis and the issue is not listed in CISA KEV, but the CVSS 7.5 score and network-reachable, unauthenticated nature warrant timely patching.
Memory exhaustion in BIND 9 resolver allows unauthenticated remote attackers to cause denial of service by querying specially crafted domains, affecting versions 9.20.0-9.20.20, 9.21.0-9.21.19, and 9.20.9-S1-9.20.20-S1. The vulnerability stems from improper memory management (CWE-772) and can be triggered without authentication or user interaction. Patches are available for affected Ubuntu, SUSE, and Debian systems.
BIND resolver servers performing DNSSEC validation can be forced into excessive CPU consumption when encountering a maliciously crafted DNS zone, resulting in denial of service. The vulnerability affects BIND 9 versions from 9.11.0 through current versions across multiple branches (9.16.50, 9.18.46, 9.20.20, 9.21.19) including BIND Supported Preview Edition variants. The CVSS score of 7.5 indicates high availability impact with network-based exploitation requiring no authentication, though no active exploitation (KEV) or proof-of-concept availability has been indicated in the provided data.
Availability loss in ISC BIND 9 DNS server arises when a stored DNS key record containing the PRIVATEDNS algorithm (algorithm number 253) carries a malformed identifier length field that exceeds the actual identifier data. BIND accepts the structurally invalid record without rejecting it at ingestion time, but when it subsequently attempts to render that record to text - during logging, zone display, or similar operations - the inconsistent length triggers a reachable assertion (CWE-617) that causes BIND to abort and exit. No active exploitation has been confirmed (not listed in CISA KEV) and no public exploit code has been identified at time of analysis; however, BIND 9 spans a very wide version range and is critical infrastructure, making patch urgency high despite the medium CVSS score of 6.5.
DNSSEC integrity bypass in ISC BIND 9 enables network-positioned attackers to forge authenticated NXDOMAIN responses by exploiting improper validation of NSEC3 records originating from child zones. Affected are BIND 9 versions across the 9.18, 9.20, and 9.21 branches, as well as the BIND 9 Supported Preview Edition (S-series). Because the CVSS vector carries S:C (scope changed), the integrity impact propagates beyond the resolver itself to any DNS client trusting BIND's DNSSEC-validated answers. No public exploit code has been identified and the vulnerability is not listed in the CISA KEV catalog at time of analysis.
Resource exhaustion in ISC BIND 9's resolver state machine allows remote unauthenticated attackers to trigger an unbounded resend loop by sending crafted DNS queries that activate bad-server retry conditions, degrading resolver availability. Multiple active release branches are affected across standard and Subscription Edition builds spanning versions 9.18.36 through 9.21.21. No public exploit has been identified and the vulnerability is not listed in CISA KEV; however, the fully network-accessible, zero-authentication attack vector makes every exposed BIND 9 resolver a potential target.
Denial of service in ISC BIND 9 resolvers can be triggered when a SIG(0)-signed DNS message is dropped under recursive-clients pressure, creating a race that leads to a use-after-free on the discarded message buffer. Affects BIND 9.20.0-9.20.22, 9.21.0-9.21.21, and the 9.20.9-S1-9.20.22-S1 subscription branch; no public exploit identified at time of analysis and the issue is not on CISA KEV.
Amplified resource exhaustion in ISC BIND 9 resolvers enables remote unauthenticated attackers to cause disproportionate resource consumption by directing a victim resolver to query a specially crafted authoritative DNS zone. All major BIND 9 resolver branches are affected, spanning versions 9.11.x through 9.21.x including BIND 9 Supported (S1) variants, representing a broad deployment footprint across enterprise and ISP resolver infrastructure. No public exploit has been identified at time of analysis and the vulnerability is not listed in CISA KEV; ISC has released patched versions.
A use-after-return vulnerability in ISC BIND 9's SIG(0) DNS query handler allows an attacker with low-level authentication privileges to manipulate ACL matching logic, potentially bypassing default-allow access controls and gaining unauthorized access to DNS services. The vulnerability affects BIND 9 versions 9.20.0-9.20.20, 9.21.0-9.21.19, and their security branches (9.20.9-S1-9.20.20-S1), while older stable releases (9.18.x) are unaffected. Vendor patches are available, and the moderate CVSS 5.4 score reflects limited technical impact when ACLs are properly configured with fail-secure defaults.
BIND 9 DNS server crashes when processing specially crafted TSIG-authenticated queries containing TKEY records, affecting versions 9.20.0-9.20.20, 9.21.0-9.21.19, and 9.20.9-S1-9.20.20-S1 on Ubuntu, SUSE, and Debian systems. An authenticated attacker with a valid TSIG key can trigger a denial of service by sending a malformed query, disrupting DNS resolution services. A patch is available for affected installations.