https://vulnerability.circl.lu Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Thu, 01 Oct 2026 05:16:59 +0000 https://vulnerability.circl.lu/vuln/cve-2026-46274 <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>io-wq: check that the predecessor is hashed in io_wq_remove_pending()</p> <p>io_wq_remove_pending() needs to fix up wq-&gt;hash_tail[] if the cancelled work was the tail of its hash bucket. When doing this, it checks whether the preceding entry in acct-&gt;work_list has the same hash value, but never checks that the predecessor is hashed at all. io_get_work_hash() is simply atomic_read(&amp;work-&gt;flags) &gt;&gt; IO_WQ_HASH_SHIFT, and the hash bits are never set for non-hashed work, so it returns 0. Thus, when a hashed bucket-0 work is cancelled while a non-hashed work is its list predecessor, the check spuriously passes and a pointer to the non-hashed io_kiocb is stored in wq-&gt;hash_tail[0].</p> <p>Because non-hashed work is dequeued via the fast path in io_get_next_work(), which never touches hash_tail[], the stale pointer is never cleared. Therefore, after the non-hashed io_kiocb completes and is freed back to req_cachep, wq-&gt;hash_tail[0] is a dangling pointer. The io_wq is per-task (tctx-&gt;io_wq) and survives ring open/close, so the dangling pointer persists for the lifetime of the task; the next hashed bucket-0 enqueue dereferences it in io_wq_insert_work() and wq_list_add_after() writes through freed memory.</p> <p>Add the missing io_wq_is_hashed() check so a non-hashed predecessor never inherits a hash_tail[] slot.</p> <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>io-wq: check that the predecessor is hashed in io_wq_remove_pending()</p> <p>io_wq_remove_pending() needs to fix up wq-&gt;hash_tail[] if the cancelled work was the tail of its hash bucket. When doing this, it checks whether the preceding entry in acct-&gt;work_list has the same hash value, but never checks that the predecessor is hashed at all. io_get_work_hash() is simply atomic_read(&amp;work-&gt;flags) &gt;&gt; IO_WQ_HASH_SHIFT, and the hash bits are never set for non-hashed work, so it returns 0. Thus, when a hashed bucket-0 work is cancelled while a non-hashed work is its list predecessor, the check spuriously passes and a pointer to the non-hashed io_kiocb is stored in wq-&gt;hash_tail[0].</p> <p>Because non-hashed work is dequeued via the fast path in io_get_next_work(), which never touches hash_tail[], the stale pointer is never cleared. Therefore, after the non-hashed io_kiocb completes and is freed back to req_cachep, wq-&gt;hash_tail[0] is a dangling pointer. The io_wq is per-task (tctx-&gt;io_wq) and survives ring open/close, so the dangling pointer persists for the lifetime of the task; the next hashed bucket-0 enqueue dereferences it in io_wq_insert_work() and wq_list_add_after() writes through freed memory.</p> <p>Add the missing io_wq_is_hashed() check so a non-hashed predecessor never inherits a hash_tail[] slot.</p> https://vulnerability.circl.lu/vuln/cve-2026-46274