All vulnerabilities
CVE-2023-4911

GNU C Library Buffer Overflow Vulnerability

GNU GNU C Library
Open in ThreatlineRecord JSON
CVSS
7.8High
ExploitationExploited in the wildAdded to KEV 21 Nov 2023CISA KEV
Exploit odds (EPSS)63.8%Chance of exploitation activity in the next 30 days, higher than 99% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2.39Fixed versionCVE List
Federal deadline12 Dec 2023Remediation due date for US federal agenciesCISA KEV
CISA required actionApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. CISA KEV

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Timeline

  1. 3 Oct 2023Exploit code publicMetasploit
  2. 3 Oct 2023, 17:25 UTCPublishedCVE List
  3. 21 Nov 2023Added to CISA KEVCISA KEV

Public exploit code and templates 2

  • Exploit moduleGlibc Tunables Privilege Escalation CVE-2023-4911 (aka Looney Tunables) 3 Oct 2023Metasploit
  • Local exploitglibc 2.38 - Buffer Overflow 11 Feb 2026Exploit-DB

Listed so defenders can prioritize. Threatline links to the source and does not host exploit code.

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.

Text from CVE List

Affected versions 8

  • Productaffected: 2.34 before 2.39CVE List
  • Red Hat Enterprise Linux 8unaffected: 0:2.28-225.el8_8.6 and laterCVE List
  • Red Hat Enterprise Linux 8.6 Extended Update Supportunaffected: 0:2.28-189.6.el8_6 and laterCVE List
  • Red Hat Enterprise Linux 9unaffected: 0:2.34-60.el9_2.7 and laterCVE List
  • Red Hat Enterprise Linux 9.0 Extended Update Supportunaffected: 0:2.34-28.el9_0.4 and laterCVE List
  • Red Hat Virtualization 4 for Red Hat Enterprise Linux 8unaffected: 0:2.28-189.6.el8_6 and laterCVE List
  • Red Hat Virtualization 4 for Red Hat Enterprise Linux 8unaffected: 0:4.5.3-10.el8ev and laterCVE List
  • Red Hat Virtualization 4 for Red Hat Enterprise Linux 8unaffected: 0:4.5.3-202312060823_8.6 and laterCVE List

References 21