GNU C Library Buffer Overflow Vulnerability
A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.
What happened
A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.
CISA lists it as exploited, added 21 Nov 2023.
Does it affect you
Names Red Hat Enterprise Linux, Canonical Ubuntu. Enter the product and version you run to place it against the affected range the vendor published.
What to do
- Apply the vendor patch named in this advisory.
bugzilla.redhat.com - Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
cisa.gov
CISA’s notes for this entry:
- 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: sourceware.org/git/?p=glibc.git
- h=1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa,: access.redhat.com/security/cve/cve-2023-4911,
- nvd.nist.gov/vuln/detail/CVE-2023-4911
Affected, as published to NVD
- rhel
- Red Hat Enterprise Linux: exactly 8.0
- ubuntu
- Canonical Ubuntu: exactly 22.04
The record
- NVD status
- Analyzed
- Published
- 03 Oct 2023, last modified 14 Oct 2026 (NVD)
- Severity
- CVSS 3.1 base score 7.8, High — computed here from the vector; NVD states 7.8.
- Vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness
- CWE-122 Heap-based Buffer Overflow, CWE-787 Out-of-bounds Write (NVD; names by MITRE)
- Exploitation
- Listed in CISA’s Known Exploited Vulnerabilities catalogue since 21 Nov 2023; federal remediation due 12 Dec 2023. CISA entry
- Exploit probability
- EPSS 63.8%, 99th percentile — FIRST, scored 23 Oct 2026. FIRST EPSS
- Vendor
- GNU · GNU C Library (CISA)
References on the NVD record
- bugzilla.redhat.com/show_bug.cgi?id=2238352Issue TrackingPatch
- access.redhat.com/errata/RHSA-2023:5453Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5454Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5455Third Party Advisory
- access.redhat.com/errata/RHSA-2023:5476Third Party Advisory
- access.redhat.com/errata/RHSA-2024:0033Third Party Advisory
- access.redhat.com/security/cve/CVE-2023-4911Third Party Advisory
- qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-glibc-ld-so.txtExploitThird Party Advisory
- qualys.com/cve-2023-4911/Third Party Advisory
- packetstormsecurity.com/files/174986/glibc-ld.so-Local-Privilege-Escalation.htmlExploitThird Party AdvisoryVDB Entry
- packetstormsecurity.com/files/176288/Glibc-Tunables-Privilege-Escalation.htmlExploitThird Party AdvisoryVDB Entry
- seclists.org/fulldisclosure/2023/Oct/11ExploitMailing ListThird Party Advisory
- security.gentoo.org/glsa/202310-03Third Party Advisory
- security.netapp.com/advisory/ntap-20231013-0006/Third Party Advisory
- exploit-db.com/exploits/52479ExploitThird Party AdvisoryVDB Entry
- cert-portal.siemens.com/productcert/html/ssa-082556.htmlThird Party Advisory
- cert-portal.siemens.com/productcert/html/ssa-794697.htmlThird Party Advisory
- cert-portal.siemens.com/productcert/html/ssa-831302.htmlThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4911US Government Resource
- openwall.com/lists/oss-security/2023/10/03/2ExploitMailing List
Sources
The verdict above is computed from the products and versions you entered and the affected ranges the vendor published to NVD. It does not inspect your environment, and this site never reports a product as unaffected: why.