CVE-2023-6546: Red Hat Enterprise Linux 8 · Use After Free
Affects Red Hat Enterprise Linux 8Source CVE Database V5
Not known to be exploited · CVSS 7.0 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 21 Dec 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
- Apply official patches and updates from Red Hat as soon as they become available to address CVE-2023-6546.
- Restrict local user access to trusted personnel only, minimizing the risk of local exploitation.
- Disable the gsm line discipline if it is not required for operational purposes to reduce the attack surface.
- Implement strict access controls and monitoring on ioctl system calls, particularly GSMIOC_SETCONF, to detect anomalous or concurrent usage patterns.
- Employ kernel security modules (e.g., SELinux) to enforce least privilege and limit the capabilities of local users.
- Conduct regular audits of local user activities and system logs to identify potential exploitation attempts.
- For embedded or telecom devices using GSM multiplexing, ensure firmware and kernel components are updated and hardened against race conditions.
- Educate system administrators about the risks of race conditions and use-after-free vulnerabilities to improve incident response readiness.
Description
A race condition was found in the GSM 0710 tty multiplexor in the Linux kernel. This issue occurs when two threads execute the GSMIOC_SETCONF ioctl on the same tty file descriptor with the gsm line discipline enabled, and can lead to a use-after-free problem on a struct gsm_dlci while restarting the gsm mux. This could allow a local unprivileged user to escalate their privileges on the system.
References
- access.redhat.com/errata/RHSA-2024:0930 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0937 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1018 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1019 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1055 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1250 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1253 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1306 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1607 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1612 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:1614 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2093 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2394 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2621 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2697 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:4577 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:4729 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:4731 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:4970 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2023-6546 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2255498 (opens in a new tab)
- github.com/torvalds/linux/commit/3c4f8333b582487a2d1e02171f1465531cde53e3 (opens in a new tab)
- zerodayinitiative.com/advisories/ZDI-CAN-20527 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/10/18 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/10/21 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/11/7 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/11/9 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/12/1 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/12/2 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/16/2 (opens in a new tab)
- openwall.com/lists/oss-security/2024/04/17/1 (opens in a new tab)