CVE-2026-31742 Linux CVE debrief

Who should care

System administrators and security teams responsible for Linux systems, particularly those with untrusted input or elevated privileges, should assess exposure and apply patches or updates. The vulnerability impacts system stability and security, especially in environments where console resize operations are common or where system uptime is critical. Security teams should prioritize patching systems with untrusted input or elevated privileges.

Why it matters

The Linux kernel vulnerability CVE-2026-31742 allows for a kernel oops when handling console resize operations after switching between alternate screens, impacting system stability and security.

• Verify console resize operations are properly handled
• Assess exposure of Linux systems to potential kernel oops
• Prioritize patching systems with untrusted input or elevated privileges

Technical summary

The Linux kernel vulnerability occurs when the console dimensions change while in the alternate screen, causing a stale unicode buffer to be restored, leading to a kernel oops. The vulnerability allows for a kernel oops when handling console resize operations after switching between alternate screens. This happens because vc_do_resize() skips reallocating the unicode buffer when vc_uni_lines is NULL, but vc_saved_uni_lines still points to the old buffer allocated for the original dimensions. When leave_alt_screen() restores vc_saved_uni_lines, the buffer dimensions no longer match vc_rows/vc_cols.

Defensive priority

Apply patches or updates from Linux to address the vulnerability, prioritizing systems with untrusted input or elevated privileges.

Recommended defensive actions

• Apply patches or updates from Linux to address the vulnerability
• Prioritize patching systems with untrusted input or elevated privileges
• Review system logs for signs of exploitation
• Verify console resize operations are properly handled
• Assess exposure of Linux systems to potential kernel oops
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the vulnerability, including a description of the issue and affected versions. The Linux kernel vulnerability occurs when the console dimensions change while in the alternate screen, causing a stale unicode buffer to be restored, leading to a kernel oops. The vulnerability allows for a kernel oops when handling console resize operations after switching between alternate screens. The issue is resolved by checking whether the console dimensions changed while in the alternate screen and,

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.