CVE-2026-99270 is a vulnerability in Linux Kernel
Published on November 3, 2026
tcp: Fix potential UAF in reqsk_timer_handler().
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.
Products Associated with CVE-2026-99270
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Affected Versions
Linux:- Version 83fccfc3940c4a2db90fd7e7079f5b465cd8c6af and below 97c8a3c1f73d828de43a5a88e8a9a143efb2b661 is affected.
- Version d3a1196bfc462943694623412d8e03aaf172bdc1 is affected.
- Version 4.1.11 and below 4.2 is affected.
- Version 4.2 is affected.
- Before 4.2 is unaffected.
- Version 7.1, <= * is unaffected.