EUVD-2026-80783
GHSA-qrrf-rhq5-mvxv
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Remote unauthenticated resolver processing of malicious DNSSEC data (AV:N/AC:L/PR:N); availability-only with A:L because default record/type limits cap the impact to degradation, not full outage.
Primary rating from Vendor (isc).
CVSS VectorNVD
Lifecycle Timeline
4DescriptionNVD
A BIND recursive resolver may experience excessive resource consumption if it encounters large numbers of a particular kind of invalid DNSSEC record. Default limits on "max-records-per-type" and "max-types-per-name" help mitigate the exposure. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
AnalysisAI
Resource exhaustion in ISC BIND 9 recursive resolvers allows a remote, unauthenticated attacker to degrade name-resolution service by causing the resolver to process responses that contain large numbers of a specific class of invalid DNSSEC record, driving excessive CPU and memory consumption (CVSS 3.1 base 5.3, AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L). Affected builds are 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, plus subscription (-S1) equivalents 9.11.3-S1 through 9.18.50-S1 and 9.20.9-S1 through 9.20.27-S1; authoritative-only deployments are not the described target. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the target to be running BIND 9 as a recursive resolver (authoritative-only configurations are not the described target) and requires the attacker to cause the resolver to process a response containing large numbers of a particular kind of invalid DNSSEC record - typically by operating or influencing an authoritative server the resolver queries, or by inducing lookups against attacker-controlled zones. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The provided CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L) and 5.3 base score are internally consistent and well-calibrated: this is a remote, unauthenticated, availability-only issue with LOW impact. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade to a fixed vendor release: BIND 9.20.29 (https://downloads.isc.org/isc/bind9/9.20.29) or BIND 9.21.26 (https://downloads.isc.org/isc/bind9/9.21.26); subscription (-S1) customers should follow the corresponding fixed build identified in the ISC advisory at https://kb.isc.org/docs/cve-2026-19668, since the published download references cover the open-source trains only. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-407 – Inefficient Algorithmic Complexity
View allSame technique Denial Of Service
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External POC / Exploit Code
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