CVE-2023-4911 — GNU C Library Buffer Overflow Vulnerability

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 — bugzilla.redhat.com (NIST National Vulnerability Database)

CISA required action CISA

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

US federal deadline: Dec 12, 2023 — passed 1038 day(s) ago

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 (Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora…).
2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
3. Apply the fixed version or the patch documented under Remediation.
4. EPSS ahead of 99% of scored CVEs: prioritize it in the patch queue.
5. 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 →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 63.77%

Detection

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

• Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
• Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
• Hunt retroactively in logs from before Nov 21, 2023 (KEV listing): exploitation may have started earlier.

Timeline

What happened to this CVE, newest first.

• 2026
• Fix documented
  Oct 13, 2026 · NIST National Vulnerability Database
• Affected products added · netapp/bootstrap os, siemens/simatic s7-1500 cpu 1518-4 pn/dp mfp firmware, siemens/simatic s7-1500 cpu 1518f-4 pn/dp mf
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · Published → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Record published
  Oct 13, 2026
• Affected products added · red hat/red hat enterprise linux 8, red hat/red hat enterprise linux 8.6 extended update support, red hat/red hat enterp
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• CVSS changed · 7.8
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Source status changed · → Published
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Added to CISA KEV (detected)
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• Record created in this database
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• 2023
• Added to CISA KEV catalog
  Nov 20, 2023 · CISA
• CVE published
  Oct 3, 2023 · redhat

Source activity

Repeated readings are counted rather than listed.

• 3× References added · Oct 13, 2026 – Oct 13, 2026
• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

38 on the record

• bugzilla.redhat.com/show_bug.cgi
  issue-tracking, x_refsource_REDHAT, Issue Tracking, Patch, CVE Program (cve.org) e CISA ADP
• www.cisa.gov/known-exploited-vulnerabilities-catalog
  US Government Resource, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2023/10/14/5
  Mailing List, NIST National Vulnerability Database
• access.redhat.com/errata/RHSA-2024:0033
  vendor-advisory, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• access.redhat.com/errata/RHSA-2023:5455
  vendor-advisory, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• security.netapp.com/advisory/ntap-20231013-0006
  GitHub Security Advisories
• access.redhat.com/security/cve/CVE-2023-4911
  vdb-entry, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DFG4P7
  GitHub Security Advisories
• access.redhat.com/errata/RHBA-2024:2413
  GitHub Security Advisories
• www.exploit-db.com/exploits/52479
  Exploit, Third Party Advisory, VDB Entry, NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20231013-0006/
  Third Party Advisory, NIST National Vulnerability Database
• cert-portal.siemens.com/productcert/html/ssa-794697.html
  Third Party Advisory, NIST National Vulnerability Database
• nvd.nist.gov/vuln/detail/CVE-2023-4911
  GitHub Security Advisories
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NDAQWH
  Mailing List, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NDAQWH
  GitHub Security Advisories
• packetstormsecurity.com/files/174986/glibc-ld.so-Local-Privilege-Escalation.html
  Exploit, Third Party Advisory, VDB Entry, NIST National Vulnerability Database
• packetstormsecurity.com/files/176288/Glibc-Tunables-Privilege-Escalation.html
  Exploit, Third Party Advisory, VDB Entry, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2023/10/14/6
  Mailing List, NIST National Vulnerability Database
• security.gentoo.org/glsa/202310-03
  Third Party Advisory, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DFG4P7
  Mailing List, NIST National Vulnerability Database
• www.qualys.com/cve-2023-4911
  GitHub Security Advisories
• www.debian.org/security/2023/dsa-5514
  Mailing List, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2023/10/05/1
  Mailing List, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2023/10/03/2
  Exploit, Mailing List, NIST National Vulnerability Database
• www.qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-g
  Exploit, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• www.openwall.com/lists/oss-security/2023/10/14/3
  Mailing List, NIST National Vulnerability Database
• www.qualys.com/cve-2023-4911/
  Third Party Advisory, CVE Program (cve.org) e CISA ADP
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4DBUQR
  GitHub Security Advisories
• cert-portal.siemens.com/productcert/html/ssa-082556.html
  Third Party Advisory, NIST National Vulnerability Database
• cert-portal.siemens.com/productcert/html/ssa-831302.html
  Third Party Advisory, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2023/10/03/3
  Mailing List, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2023/10/13/11
  Mailing List, NIST National Vulnerability Database
• github.com/advisories/GHSA-m77w-6vjw-wh2f
  GitHub Security Advisories
• access.redhat.com/errata/RHSA-2023:5454
  vendor-advisory, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• access.redhat.com/errata/RHSA-2023:5453
  vendor-advisory, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• access.redhat.com/errata/RHSA-2023:5476
  vendor-advisory, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• seclists.org/fulldisclosure/2023/Oct/11
  Exploit, Mailing List, Third Party Advisory, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4DBUQR
  Mailing List, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• Medium CVE-2026-104046 Sssd: sssd: denial of service via incomplete identity provider authentication requests 9d
• Medium CVE-2026-104045 Sssd: sssd: denial of service via race condition in autofs responder 9d
• Medium CVE-2026-104047 Sssd: sssd: information disclosure via query injection in entra id lookups 9d
• High CVE-2026-104048 Sssd: sssd: authorization bypass via cross-domain username collision in hbac evaluation 9d
• High CVE-2026-102558 Libsoup: libsoup: heap buffer overflow during websocket receive-buffer growth 16d
• High CVE-2026-102555 Libsoup: libsoup: heap buffer overflow via uninitialized length in data-uri base64 decoding 16d

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-2023-4911 is "GNU C Library Buffer Overflow Vulnerability", rated High. It affects Ubuntu Linux (Canonical); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 7.8 describes technical severity. EPSS 63.77% 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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