EUVD-2026-80786
GHSA-crh2-6h8j-h25c
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Remote unauthenticated resolver-side memory growth with no confidentiality/integrity impact and gradual (not catastrophic) availability degradation warrants A:L, matching the vendor vector.
Primary rating from Vendor (isc).
CVSS VectorNVD
Lifecycle Timeline
3DescriptionNVD
In a query response, an attacker may send named multiple copies of a record that should only exist once (such as an SOA record). If the RDATA is the same on all the copies, the record is appended to the in-memory RDATA set, which can cause increased memory usage of the negative cache and possibly lead to other memory attack vectors. 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
Memory amplification in ISC BIND 9's negative cache allows remote, unauthenticated attackers to inflate resolver memory usage by supplying crafted authoritative responses. When a query response carries multiple copies of a record that should exist only once (for example an SOA record) with identical RDATA, named appends each copy to the in-memory RDATA set instead of discarding duplicates, so negative-cache entries retain more data than they should; BIND 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, plus the corresponding -S1 subscription builds, are affected. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation targets a recursive/resolving `named` and requires the attacker to control or influence the authoritative response the resolver receives - the query response must contain multiple copies of a normally-singleton record (e.g. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a genuinely moderate, low-priority issue whose signals are internally consistent. … 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 9.21.26, the fixed maintenance releases published at https://downloads.isc.org/isc/bind9/9.20.29 and https://downloads.isc.org/isc/bind9/9.21.26, and consult the ISC advisory at https://kb.isc.org/docs/cve-2026-75029 for the exact fix for each affected branch, including the 9.11/9.18 and -S1 subscription lines. … Detailed patch versions, workarounds, and compensating controls in full report. |
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