# CVE-2026-80962: dm-pcache: validate geometry fields from on-disk cache_info

> A local attacker with CAP_SYS_ADMIN can trigger out-of-bounds memory access in the Linux kernel dm-pcache module via crafted on-disk metadata, potentially leading to code execution or privilege escalation.

- **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
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-80962, DEBIAN-CVE-2026-80962, GHSA-mv2p-grx7-v5rf, UBUNTU-CVE-2026-80962

## What is CVE-2026-80962?

CVE-2026-80962 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

dm-pcache: validate geometry fields from on-disk cache_info

cache_segs_init() iterates cache_info->n_segs times indexing
cache->segments[], which is sized to the cache device geometry, and
get_seg_id() takes each segment id from the on-media cache_info and the
per-segment next_seg link. Both come from cache device metadata that is
only CRC-protected with a fixed public seed, so whoever supplies the
cache device on a table load (CAP_SYS_ADMIN) controls them: an oversized
n_segs or an out-of-range id drives an out-of-bounds access of
cache->segments[] and a wild CACHE_DEV_SEGMENT() pointer into the device
mapping -- an out-of-bounds read and write from on-disk data.

Reject an n_segs that exceeds the device segment count and a segment id
that is out of range before either is used. Valid metadata is unaffected.

## Which versions are affected by CVE-2026-80962?


## How do I fix CVE-2026-80962?

Apply the vendor's patch.

## Is CVE-2026-80962 being exploited?

There is no known exploitation of CVE-2026-80962 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80962 and fix it if it is affected.

What it is: CVE-2026-80962 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-80962 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-2026-80962/ (Markdown: https://insights.sbomify.com/CVE-2026-80962/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80962
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80962
- OSV: https://osv.dev/vulnerability/CVE-2026-80962

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80962/
Summaries are generated and may contain mistakes; the official description above is the record.