Vulnerability in Linux

CVE-2026-99270

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix potential UAF in reqsk_timer_handler(). When TCP socket migration fails at inet_ehash_insert() in reqsk_timer_handler(), we jump to the no_ownership: label and free the new reqsk immediately with __reqsk_free(). Thus, we must stop the new reqsk's timer before jumping to the label, but the timer might be missed since the cited commit, resulting in UAF. As we are in the original reqsk's timer context, we can safely call timer_delete_sync() for the new reqsk. Let's pass false to __inet_csk_reqsk_queue_drop() to stop the new reqsk's timer.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

  • Linux — versions 4.2, d3a1196bfc462943694623412d8e03aaf172bdc1

References

Frequently asked questions

What is CVE-2026-99270?
CVE-2026-99270 is a high-severity vulnerability in Linux. CVSS score: 8.1/10. Published 2026-11-03.
How severe is CVE-2026-99270?
High severity. CVSS v3 base score is 8.1 out of 10.