EUVD-2026-80743
GHSA-pqfm-7x4v-9w63
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Remote unauthenticated (AV:N/PR:N) but the timing/ordering race gives AC:H; impact is resolver abort only, so C:N/I:N/A:H.
Primary rating from Vendor (isc).
CVSS VectorNVD
Lifecycle Timeline
4DescriptionNVD
An attacker may be able to cause a named resolver to abort. The attack requires inducing the victim resolver to send multiple queries for a DNSSEC-signed zone hosted by an authoritative server under the control of the attacker. If the auth responds with a particular sequence of crafted answers, and those answers arrive in a particular order with particular timing, the named resolver will encounter a use-after-free bug, and abort. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
AnalysisAI
Denial of service in ISC BIND 9 recursive resolvers: an attacker who controls (or compromises) an authoritative server for a DNSSEC-signed zone can cause named to abort after it encounters a use-after-free when processing a specific crafted sequence of answers. The attacker must first induce the victim resolver to issue multiple queries for that attacker-hosted zone, and the malicious responses must then arrive in a particular order and timing to trip the race, which is why this is rated high complexity (AC:H) despite being remote and unauthenticated (PR:N, no user interaction). …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to control (or compromise) an authoritative server for a DNSSEC-signed zone AND to induce the victim recursive resolver to send multiple queries for that zone. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a genuine but hard-to-trigger denial-of-service issue, not a data-exposure flaw. … 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 | Vendor-released patch: upgrade to BIND 9.20.29 or later, available from ISC's download site at https://downloads.isc.org/isc/bind9/9.20.29, and consult the advisory at https://kb.isc.org/docs/cve-2026-19662 for the branch-specific guidance applicable to your deployment. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-416 – Use After Free
View allSame technique Denial Of Service
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External POC / Exploit Code
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