CVE-2023-6377: Red Hat Enterprise Linux 6 Extended Lifecycle Support – EXTENSION · Out-of-bounds Read
Affects Red Hat Enterprise Linux 6 Extended Lifecycle Support – EXTENSIONSource CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 1.5% chance of exploitation in 30 days – higher than 75% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 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 2026-10-26.
What to do
AI-suggested
Organizations should prioritize applying any available patches or updates from Red Hat addressing this vulnerability as soon as they are released. Until patches are available, it is advisable to disable or restrict X11 forwarding, especially for untrusted users or networks, to reduce the risk of remote exploitation. Limiting user privileges and enforcing the principle of least privilege can mitigate the impact of local exploitation. Monitoring and logging of X11 sessions and input device changes can help detect suspicious activities. Additionally, organizations should consider migrating from RHEL 6 Extended Lifecycle Support to more current, supported versions of Red Hat Enterprise Linux to benefit from ongoing security updates. Network segmentation and strict access controls around legacy systems can further reduce exposure. Employing application whitelisting and endpoint detection and response (EDR) solutions can help detect and prevent exploitation attempts. Finally, educating system administrators about the risks of legacy software and the importance of timely patching is critical.
Description
A flaw was found in xorg-server. Querying or changing XKB button actions such as moving from a touchpad to a mouse can result in out-of-bounds memory reads and writes. This may allow local privilege escalation or possible remote code execution in cases where X11 forwarding is involved.
References
- access.redhat.com/errata/RHSA-2023:7886 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0006 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0009 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0010 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0014 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0015 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0016 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0017 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0018 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:0020 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2169 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2170 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2995 (opens in a new tab)
- access.redhat.com/errata/RHSA-2024:2996 (opens in a new tab)
- access.redhat.com/errata/RHSA-2025:13998 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2023-6377 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2253291 (opens in a new tab)
- gitlab.freedesktop.org/xorg/xserver/-/commit/0c1a93d319558fe3ab2d94f51d174b4f93810afd (opens in a new tab)
- lists.x.org/archives/xorg-announce/2023-December/003435.html (opens in a new tab)
- openwall.com/lists/oss-security/2023/12/13/1 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2023/12/msg00008.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2023/12/msg00013.html (opens in a new tab)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6R63Z6GIWM3YUNZRCGFODUXLW3GY2HD6/ (opens in a new tab)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7PP47YXKM5ETLCYEF6473R3VFCJ6QT2S/ (opens in a new tab)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IFHV5KCQ2SVOD4QMCPZ5HC6YL44L7YJD/ (opens in a new tab)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LJDFWDB7EQVZA45XDP7L5WRSRWS6RVRR/ (opens in a new tab)
- security.gentoo.org/glsa/202401-30 (opens in a new tab)
- security.netapp.com/advisory/ntap-20240125-0003/ (opens in a new tab)
- debian.org/security/2023/dsa-5576 (opens in a new tab)