CVE-2023-2911 — Exceeding the recursive-clients quota may cause named to terminate unexpectedly when stale-answer-client-timeout is set to 0

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Documented patch — www.openwall.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Fedoraproject Fedora, Isc Bind…).
2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
3. Apply the fixed version or the patch documented under Remediation.
4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-787 · Out-of-bounds Write

Other CVEs with this weakness →

EPSS over time FIRST

Oct 24, 2026 → Oct 30, 2026 · 7 reading(s) · max 2.45%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

Timeline

What happened to this CVE, newest first.

• 2026
• Affected products added · isc/bind 9
  Oct 24, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 24, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 24, 2026
• Fix documented
  Oct 24, 2026 · NIST National Vulnerability Database
• Affected products added · isc/bind, debian/debian linux, fedoraproject/fedora, netapp/active iq unified manager, netapp/h700s firmware, netapp/h30
  Oct 24, 2026 · NIST National Vulnerability Database
• CVSS changed · 7.5
  Oct 24, 2026 · NIST National Vulnerability Database
• Source status changed · → Modified
  Oct 24, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 24, 2026 · Alertas do Telegram
• 2023
• CVE published
  Jun 21, 2023 · isc

Source activity

Repeated readings are counted rather than listed.

• 2× References added · Oct 24, 2026 – Oct 24, 2026
• 1× Official description updated · Oct 24, 2026 – Oct 24, 2026

References

11 on the record

• kb.isc.org/docs/cve-2023-2911
  Vendor Advisory, vendor-advisory, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2023/06/21/6
  Mailing List, Patch, Third Party Advisory, NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20230703-0010/
  Third Party Advisory, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3K6AJ
  Mailing List, Third Party Advisory, NIST National Vulnerability Database
• github.com/advisories/GHSA-rrr5-v5h9-fpwp
  GitHub Security Advisories
• security.netapp.com/advisory/ntap-20230703-0010
  GitHub Security Advisories
• nvd.nist.gov/vuln/detail/CVE-2023-2911
  GitHub Security Advisories
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SEFCEV
  GitHub Security Advisories
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SEFCEV
  Mailing List, Third Party Advisory, NIST National Vulnerability Database
• www.debian.org/security/2023/dsa-5439
  Third Party Advisory, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3K6AJ
  GitHub Security Advisories

Elsewhere on this site

Related CVEs (same products)

• Critical CVE-2026-111497 Google Brotli Unchecked Return Value Vulnerability KEV 8d
• High CVE-2026-97313 Specific RPZ configurations and query patterns may result in an unexpected exit 9d
• High CVE-2026-94300 Concurrent GSS-TSIG messages corrupt memory 9d
• High CVE-2026-96888 Named may terminate unexpectedly when a redirect zone is used with strict QNAME minimization 9d
• High CVE-2026-19630 Amplified resource exhaustion in inbound message processing 9d
• High CVE-2026-80274 Validating resolver can abort while caching a mismatched NOQNAME proof Sep 16, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-2911 is "Exceeding the recursive-clients quota may cause named to terminate unexpectedly when stale-answer-client-timeout is set to 0", rated High. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 2.43% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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