CVE-2022-3176 — There exists a use-after-free in io_uring in the Linux kernel

There exists a use-after-free in io_uring in the Linux kernel. Signalfd_poll() and binder_poll() use a waitqueue whose lifetime is the current task. It will send a POLLFREE notification to all waiters before the queue is freed. Unfortunately, the io_uring poll doesn't handle

01What is this vulnerability?

There exists a use-after-free in io_uring in the Linux kernel. Signalfd_poll() and binder_poll() use a waitqueue whose lifetime is the current task. It will send a POLLFREE notification to all waiters before the queue is freed. Unfortunately, the io_uring poll doesn't handle POLLFREE. This allows a use-after-free to occur if a signalfd or binder fd is polled with io_uring poll, and the waitqueue…

02Affected products

Vendor	Product	Versions
Linux	Kernel	unspecified

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2022-09-16T13:55:09.907Z
• Last modified: 2025-04-21T13:49:18.998Z

09References

• kernel.dance — https://kernel.dance/#fc78b2fc21f10c4c9c4d5d659a685710ffa63659
• git.kernel.org — https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit?h=linux-…
• www.debian.org — https://www.debian.org/security/2022/dsa-5257
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2022/11/msg00001.html
• security.netapp.com — https://security.netapp.com/advisory/ntap-20230216-0003/