CVE-2026-98858: vulnerability in Linux
io_uring: fix task_work add use-after-free with SQPOLL
Published · Updated
3Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackepss 0.2%
exploitation probability
0.2%top 95% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
io_uring: fix task_work add use-after-free with SQPOLL
For SQPOLL, the sqpoll thread runs task_work off its own list and
doesn't need to be told about it, so it can pop and complete a request
as soon as mpscq_push() has published it. If that was the last request
holding the ring alive, io_ring_exit_work() then frees the ctx, stops
the thread, and with it the tctx, while io_req_normal_work_add() is
still looking at both after the push:
BUG: KASAN: slab-use-after-free in io_req_normal_work_add+0x439/0x510
Read of size 4 at addr ff11000000ca0000 by task repro/55
(...)
BUG: KASAN: slab-use-after-free in queue_work_on+0x25/0x70
Write of size 8 at addr ff11000000c3bd00 by task repro/55
Hold an RCU read lock across the add, like io_req_local_work_add() already
does, and have io_ring_exit_work() wait for a grace period for SQPOLL rings
as well before freeing the ctx.
Affected products
Linux · LinuxRelated CVEs — Linux
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