CVE-2023-4911
GNU — GNU C Library Buffer Overflow Vulnerability
GNU · CWE-122 | CWE-787 — Out-of-bounds write · in CISA KEV since 2023-11-21
EVRS 75 of 100 Urgent
Patch This Cycle
Rank 702 of 2,960 tracked
Raised to the floor for a confirmed exploited vulnerability.
Why it scores 75
Evidence available: 6 of 7 signalsListed in the CISA KEV catalog, and an EPSS probability of 0.638.
- CISA KEVApplied
- RansomwareDid not apply
- Vendor exploitationDid not apply
- EPSSApplied
- Microsoft Exploitability IndexNot applicable
- Pre-patch disclosureNo data
- KEV recencyDid not apply
- CVSSApplied
The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data
Fix
Patch or fixed version identifiedCISA required action
- 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
- a=commitdiff
- h=1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa, https://access.redhat.com/security/cve/cve-2023-4911, https://www.debian.org/security/2023/dsa-5514
- nvd.nist.gov/…/CVE-2023-4911
Fixed in
glibc -> 2.35-0ubuntu3.4 | glibc -> 2.38-1ubuntu6 | glibc -> 2.36-9+deb12u3 | glibc -> 2.37-12
Affected versions
- glibc
>= 2.34 < 2.39 - codeready linux builder
9.0 - codeready linux builder eus
8.69.29.49.6 - codeready linux builder for arm64
9.0 aarch64 - codeready linux builder for arm64 eus
8.69.2 aarch649.4 aarch649.6 aarch64 - codeready linux builder for ibm z systems
9.0 s390x - codeready linux builder for ibm z systems eus
8.69.2 s390x9.4 s390x9.6 s390x - codeready linux builder for power little endian
9.0 ppc64le
+41 more affected products; see the full list at NVD.
Remediation
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Fixed versions from NVD.
Evidence
Each value with its source| Measure | Value | Source |
|---|---|---|
| CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. | 7.8 | NVD |
| FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. | 0.638 (99.22nd pctl) | FIRST EPSS |
| Actively exploitedWhether a source of record has confirmed attacks using it in the wild. | Confirmed | CISA KEV |
| Ransomware campaign useWhether CISA has seen ransomware operators use it. | Unknown or none | CISA KEV |
| CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. | 2023-12-12 · KEV since 2023 · listed over a year | CISA KEV |
| Public exploit moduleA module existing is not the same as active exploitation. | Public module exists | Metasploit |
| EUVD cross-referenceENISA's record: CVSS 7.8 (v3.1), assigned by redhat. | Listed | ENISA EUVD |
Description
NVDA 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 CISA says to do
- 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
- a=commitdiff
- h=1056e5b4c3f2d90ed2b4a55f96add28da2f4c8fa, https://access.redhat.com/security/cve/cve-2023-4911, https://www.debian.org/security/2023/dsa-5514
- nvd.nist.gov/…/CVE-2023-4911
Public module
Metasploit lists a public excellent-rank module for this CVE: Glibc Tunables Privilege Escalation CVE-2023-4911 (aka Looney Tunables) (linux/local/glibc_tunables_priv_esc). A module existing is not the same as active exploitation; see metasploit.com.