CVE Alert: CVE-2025-62231 – Red Hat – Red Hat Enterprise Linux 10
CVE-2025-62231
A flaw was identified in the X.Org X server’s X Keyboard (Xkb) extension where improper bounds checking in the XkbSetCompatMap() function can cause an unsigned short overflow. If an attacker sends specially crafted input data, the value calculation may overflow, leading to memory corruption or a crash.
AI Summary Analysis
Risk verdict
High risk to affected systems; exploitation requires local access and could cause memory corruption, leading to X server crashes or data exposure.
Why this matters
This integer overflow in XkbSetCompatMap can enable memory corruption with high availability impact. In multi-user, GUI-enabled environments (desktops, VDI, or VNC sessions), a local attacker could destabilise the X server and potentially access or disrupt sensitive memory contents.
Most likely attack path
Preconditions are local access with low privileges and no user interaction. An attacker would craft input to the XkbSetCompatMap pathway in the X.Org X server (or related XWayland/tigervnc components) to trigger an unsigned short overflow, causing memory corruption. With the scope unchanged, the impact remains within the present security domain, but could enable persistent disruption or facilitate further local compromise.
Who is most exposed
Workstations and servers running GUI stacks on Red Hat Enterprise Linux 6–10 with Xorg/Xwayland or VNC/X11 services are most at risk, especially in shared-user or remote-access scenarios.
Detection ideas
- Recurrent Xorg/Xwayland crashes or core dumps linked to XkbSetCompatMap.
- SIGSEGV or memory-corruption events in Xorg processes in logs/dmesg.
- Unusual spikes in Xorg memory usage or stability problems during GUI input.
- Local user activity patterns involving crafted XKB input sequences.
- Anomalous failures in remote access sessions (VNC/X11) without user actions.
Mitigation and prioritisation
- Apply the latest Red Hat security updates for affected packages (xorg-x11-server-Xwayland, tigervnc, xorg-x11-server) across RH 6–10.
- If KEV is true or EPSS ≥ 0.5 (data not provided here), treat as priority 1; otherwise treat as high-priority with a defined maintenance window.
- Validate patches in a staging environment before production rollout.
- Enforce strict local access controls; disable or limit GUI/remote-access services where feasible.
- Plan change-management steps: change freeze window, confirm backups, monitor post-patch stability and logs.
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