# CVE-2026-72107: dm era: fix out-of-bounds memory access for non-zero start sector

> A local attacker with access to a dm-era device with a non-zero start sector can trigger an out-of-bounds memory access, potentially causing a crash or code execution.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-72107, DEBIAN-CVE-2026-72107, GHSA-pp8j-c3wv-r68r, UBUNTU-CVE-2026-72107

## What is CVE-2026-72107?

CVE-2026-72107 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

dm era: fix out-of-bounds memory access for non-zero start sector

dm-era tracks writes in target-relative blocks, but era_map() calculates
the writeset block before applying the target offset.  Tables with a
non-zero start sector can therefore pass an absolute mapped-device block
to metadata_current_marked().

If the absolute block is beyond the current writeset size,
writeset_marked() tests past the end of the in-core bitset.  KASAN reports
this as a vmalloc-out-of-bounds access.

Apply the target offset before calculating the era block so writeset
lookups use the target-relative block number.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-72107?


## How do I fix CVE-2026-72107?

Apply the vendor's patch.

## Is CVE-2026-72107 being exploited?

There is no known exploitation of CVE-2026-72107 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72107 and fix it if it is affected.

What it is: CVE-2026-72107 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72107 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-2026-72107/ (Markdown: https://insights.sbomify.com/CVE-2026-72107/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72107
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72107
- OSV: https://osv.dev/vulnerability/CVE-2026-72107

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72107/
Summaries are generated and may contain mistakes; the official description above is the record.