# CVE-2026-52914: batman-adv: fix fragment reassembly length accounting

> A local attacker can cause a denial of service in the Linux kernel by exploiting an integer overflow in batman-adv fragment reassembly length accounting.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jun 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-90821, BELL-CVE-2026-52914, DEBIAN-CVE-2026-52914, GHSA-637x-w8p5-96wm, ROOT-OS-DEBIAN-11-CVE-2026-52914, ROOT-OS-DEBIAN-12-CVE-2026-52914, ROOT-OS-UBUNTU-2204-CVE-2026-52914, ROOT-OS-UBUNTU-2404-CVE-2026-52914, UBUNTU-CVE-2026-52914

## What is CVE-2026-52914?

CVE-2026-52914 is a critical vulnerability in Linux kernel, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

batman-adv: fix fragment reassembly length accounting

batman-adv keeps a running payload length for queued fragments and uses it
to validate a fragment chain before reassembly.

That accounting currently allows the accumulated fragment length to be
truncated during updates. As a result, malformed fragment chains can
bypass the intended validation and drive reassembly with inconsistent
length state, leading to a local denial of service.

Fix the accounting by storing the accumulated length in a length-typed
field and rejecting update overflows before the existing validation logic
runs.

The fix was verified against the original reproducer and against valid
fragment reassembly paths.

Weakness: CWE-787 (Out-of-bounds Write), CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-52914?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-52914?

Apply the vendor's patch.

## Is CVE-2026-52914 being exploited?

There is no known exploitation of CVE-2026-52914 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52914 and fix it if it is affected.

What it is: CVE-2026-52914 is a critical vulnerability in Linux kernel, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-52914 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-52914/ (Markdown: https://insights.sbomify.com/CVE-2026-52914/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52914
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52914
- OSV: https://osv.dev/vulnerability/CVE-2026-52914

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52914/
Summaries are generated and may contain mistakes; the official description above is the record.