CISA KEV source record / CVE-2023-4911

GNU C Library Buffer Overflow Vulnerability

GNU / GNU C Library

Known exploitation catalogNot a Secureline discoveryNot a live alert

GNU C Library's dynamic loader ld.so contains a buffer overflow vulnerability when processing the GLIBC_TUNABLES environment variable, allowing a local attacker to execute code with elevated privileges.

CVE identifier: CVE-2023-4911
Added to KEV: Nov 21, 2023
CISA catalog dueDate: Dec 12, 2023

The dates above are catalog fields. The addition date does not establish when the vulnerability was discovered or first exploited. Confirm which requirements apply to your organisation separately.

Publisher's required action

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

This wording is attributed to the CISA snapshot. Verify current vendor guidance, affected versions and your deployment before applying changes.

Keep the signals separate.

Ransomware use, as reported by CISA: Unknown
CVSS severity: Not supplied by KEV
EPSS probability: Not available

No EPSS value was supplied for this record in the current snapshot. Unknown values are not treated as zero.

“Unknown” ransomware use is an unknown source field, not proof that ransomware activity has not occurred.

Source notes

This vulnerability affects a common open-source component, third-party library, or a protocol used by different products. Please check with specific vendors for information on patching status. For more information, please see: https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa, https://access.redhat.com/security/cve/cve-2023-4911, https://www.debian.org/security/2023/dsa-5514 ; https://nvd.nist.gov/vuln/detail/CVE-2023-4911

Source & freshness

Catalog version 2026.11.06
Source updated: Nov 6, 2026, 7:44 PM UTC
Successfully checked: Nov 7, 2026, 6:22 PM UTC

CISA source snapshot ↗CVE record ↗EPSS methodology ↗

Automated source record, not an editorial advisory or an independent discovery. No affected or fixed version is inferred, and no organisation-specific risk rating is generated.