CVE-2026-97941

In the Linux kernel, the following vulnerability has been resolved: mm/slab: take n->list_lock in __slab_try_return_freelist() to avoid race Commit ba7425312607 ("mm, slab: add an optimistic __slab_try_return_freelist()") incorrectly assumed that nobody has freed an object to the slab as long as slab->freelist is NULL and cmpxchg succeeds. However, as reported by Hyunwoo Kim [1], other CPUs might have freed an object to the slab, insert the slab to the partial list, then allocated an object from the slab, and be in the middle of removing the slab from the list under n->list_lock. Since __refill_objects_node() puts the slab back on pc.slabs outside n->list_lock, it might insert the slab into that list while the slab is concurrently being removed from n->partial. This led to a list corruption [1]: list_add corruption. next->prev should be prev (ffff888100000248), but was dead000000000122. (next=ffffea000416e410). kernel BUG at lib/list_debug.c:29! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 1 UID: 65534 PID: 144 Comm: poc Not tainted 7.2.0-16172-gcf72cbb39da8-dirty #1 PREEMPT(lazy) RIP: 0010:__list_add_valid_or_report+0x80/0xd0 ... Call Trace: alloc_from_new_slab+0x183/0x300 ___slab_alloc+0x31c/0x890 __kmalloc_noprof+0x3d4/0x800 lsm_blob_alloc+0x2d/0x50 security_msg_msg_alloc+0x26/0x90 load_msg+0x1aa/0x210 do_msgsnd+0x91/0x800 do_syscall_64+0x109/0x5d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f ... Kernel panic - not syncing: Fatal exception This is a classic ABA problem where cmpxchg succeeds but the state has changed since __refill_objects_node() took the freelist from the slab. As Vlastimil Babka mentioned [2], it should be rare to return more than one slab (due to the racy read of slab->counters in get_partial_node_bulk()). Therefore, instead of introducing additional complexity, acquire and release n->list_lock twice in the worst case. Return the slab directly to the partial list and hold n->list_lock across the cmpxchg and add_partial(). This is similar to the initial version of commit ba7425312607 [3]. This is enough to avoid the race as the list manipulation is serialized by n->list_lock. While at it, bring back unlikely() hint now that the condition is unlikely.

• https://git.kernel.org/stable/c/4a724bcf5d703e18957397914d79156fa2cf1174
• https://git.kernel.org/stable/c/570a6aaf6b52c6ec098f4811cdb52b1496f13d15

Published

Sep 25, 2026

Last Modified

Sep 25, 2026

Status

Received

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-97936In the Linux kernel, the following vulnerability has been re…
• CVE-2026-97937In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-97938In the Linux kernel, the following vulnerability has been re…
• CVE-2026-97939In the Linux kernel, the following vulnerability has been re…
• CVE-2026-9794A flaw was found in Keycloak. A remote, unauthenticated atta…5.3
• CVE-2026-97940In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-97942In the Linux kernel, the following vulnerability has been re…
• CVE-2026-97943In the Linux kernel, the following vulnerability has been re…
• CVE-2026-97944In the Linux kernel, the following vulnerability has been re…
• CVE-2026-97945In the Linux kernel, the following vulnerability has been re…
• CVE-2026-97946In the Linux kernel, the following vulnerability has been re…
• CVE-2026-97947In the Linux kernel, the following vulnerability has been re…