Root privilege escalation via tunables parsing overflow
Published Oct 3, 2023 · Updated Jul 14, 2026
Heap buffer overflow in GNU C Library 2.34 through 2.38 allows local users to execute code as root through SUID programs. ld.so's parse_tunables() fails to advance its input pointer after a name=value pair without a colon, then appends the value again beyond the duplicated GLIBC_TUNABLES buffer. Exploitation requires local low-privileged access and a SUID-root binary, and successful corruption makes the loader trust an attacker-controlled library path.
Summary
What happened
Heap buffer overflow in GNU C Library 2.34 through 2.38 allows local users to execute code as root through SUID programs. ld.so's parse_tunables() fails to advance its input pointer after a name=value pair without a colon, then appends the value again beyond the duplicated GLIBC_TUNABLES buffer. Exploitation requires local low-privileged access and a SUID-root binary, and successful corruption makes the loader trust an attacker-controlled library path.
The record
- CVE
- CVE-2023-4911
- Published
- Oct 3, 2023
- Updated
- Jul 14, 2026
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 8
- Classifications
- CWE-122, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 3, 2023CVE publishedPublication date reported by the CVE source.
- Nov 21, 2023Exploitation reportedCISA Known Exploited Vulnerabilities Catalog entry
- Jul 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- RickdeJager CVE-2023-4911 proof of conceptproof of concept · demonstrated
- Metasploit glibc Tunables privilege-escalation moduleweaponized · validated
- leesh3288 Looney Tunables PoCproof of concept · demonstrated
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Reported exploitation
- CISA Known Exploited Vulnerabilities Catalog entryknown exploited catalog
Technologies
Your stack
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Your stack
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