GNU · GNU C Library
CVE-2023-4911
Glibc: buffer overflow in ld.so leading to privilege escalation
What it is
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: 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.
What to do
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Deadline for US federal agencies: December 12, 2023
- Added to the CISA list
- November 21, 2023
- Published
- October 3, 2023
- Severity
- High 7.8 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 64% in the top 0.8% of all known vulnerabilities
- Weakness
- CWE-122
- More details
- NVD · CVE.org · CISA
All references (9)
- https://access.redhat.com/errata/RHSA-2023:5453
- https://access.redhat.com/errata/RHSA-2023:5454
- https://access.redhat.com/errata/RHSA-2023:5455
- https://access.redhat.com/errata/RHSA-2023:5476
- https://access.redhat.com/errata/RHSA-2024:0033
- https://access.redhat.com/security/cve/CVE-2023-4911
- https://bugzilla.redhat.com/show_bug.cgi?id=2238352
- https://www.qualys.com/2023/10/03/cve-2023-4911/looney-tunables-local-privilege-escalation-glibc-ld-so.txt
- https://www.qualys.com/cve-2023-4911/
More exploited flaws from GNU
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Jan 26, 2026 | Argument Injection | InetUtils | Critical 9.8 | 99% |
| Oct 2, 2025 | Bash OS Command Injection | GNU Bash | High 8.8 | 99.7% |
| Jan 28, 2022 | Arbitrary Code Execution | Bourne-Again Shell (Bash) | Critical 9.8 | >99.9% |
| Jan 28, 2022 | Arbitrary Code Execution | Bourne-Again Shell (Bash) | Critical 9.8 | 99.9% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.