CVE-2023-4911: GNU C Library Buffer Overflow Vulnerability
Affects GNU GNU C LibrarySource CISA KEV
Exploited in the wild · KEV due 12 Dec 2023 · public exploit available (Metasploit, Exploit-DB) · 63% EPSS : apply the vendor's fix or mitigations to GNU C Library now.
Data as of 10/24/2026, 22:15:59 UTC
- Exploitation
Actively exploited – in CISA KEV since 11/21/2023
- KEV deadline
- 12/12/2023 US federal agencies must patch by this date; a sensible deadline for everyone else.
- EPSS
- 63.7% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Public exploits
- 1 Metasploit module, 1 Exploit-DB entryPublic attack or detection tooling exists; see Public exploits below.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HWhat to do
CISA required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Public exploits and detection
Metasploit modules
Public tooling indexed from Metasploit Framework, Exploit-DB and ProjectDiscovery nuclei-templates. Its existence raises the odds of exploitation; it does not confirm attacks.
Description
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.
Weaknesses
- CWE-122Heap-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #16
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
References
- sourceware.org/git/?p=glibc.git (opens in a new tab)
- access.redhat.com/security/cve/cve-2023-4911, (opens in a new tab)
- debian.org/security/2023/dsa-5514 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2023-4911 (opens in a new tab)
- cisa.gov/known-exploited-vulnerabilities-catalog?search=CVE-2023-4911 (opens in a new tab)