# CVE-2026-99051: fsverity: RCU-delay the freeing of struct fsverity_info


- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-99051, GHSA-7hq4-c7jg-2h9h, UBUNTU-CVE-2026-99051

## What is CVE-2026-99051?

CVE-2026-99051 is a high-severity vulnerability in Linux, published on 23 Oct 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

fsverity: RCU-delay the freeing of struct fsverity_info

__fsverity_get_info() calls rhashtable_lookup_fast(), which just uses
rcu_read_lock() and doesn't directly synchronize with
fsverity_remove_info().

For the same inode this isn't a problem: its fsverity_info is removed
only at inode eviction time or upon failure to enable verity, when the
inode no longer needs its fsverity_info and it will no longer be
accessed via that inode.

However, this is broken and can cause a use-after-free for concurrent
__fsverity_get_info() for *different* inodes.  Those rely on following
fsverity_info::rhash_head in the rhashtable under rcu_read_lock() only.
They also use fsverity_info::inode to do the key comparison.

Fix this by RCU-delaying the freeing of 'struct fsverity_info' after
it's been removed from the rhashtable.

## Which versions are affected by CVE-2026-99051?


## How do I fix CVE-2026-99051?

Upgrade to a fixed version.

## Is CVE-2026-99051 being exploited?

There is no known exploitation of CVE-2026-99051 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99051 and fix it if it is affected.

What it is: CVE-2026-99051 is a high-severity vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99051 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-99051/ (Markdown: https://insights.sbomify.com/CVE-2026-99051/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99051
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99051
- OSV: https://osv.dev/vulnerability/CVE-2026-99051

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99051/
Summaries are generated and may contain mistakes; the official description above is the record.