# CVE-2026-23416: mm/mseal: update VMA end correctly on merge

> Incorrect VMA end calculation during memory sealing merges can lead to inconsistent memory state, requiring a kernel patch.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 2 Apr 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-23416, DEBIAN-CVE-2026-23416, GHSA-h9cv-r6cj-w8vj, UBUNTU-CVE-2026-23416

## What is CVE-2026-23416?

CVE-2026-23416 is a medium-severity vulnerability in Linux kernel, published on 2 Apr 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:

mm/mseal: update VMA end correctly on merge

Previously we stored the end of the current VMA in curr_end, and then upon
iterating to the next VMA updated curr_start to curr_end to advance to the
next VMA.

However, this doesn't take into account the fact that a VMA might be
updated due to a merge by vma_modify_flags(), which can result in curr_end
being stale and thus, upon setting curr_start to curr_end, ending up with
an incorrect curr_start on the next iteration.

Resolve the issue by setting curr_end to vma->vm_end unconditionally to
ensure this value remains updated should this occur.

While we're here, eliminate this entire class of bug by simply setting
const curr_[start/end] to be clamped to the input range and VMAs, which
also happens to simplify the logic.

## Which versions are affected by CVE-2026-23416?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23416?

Apply the vendor's patch.

## Is CVE-2026-23416 being exploited?

There is no known exploitation of CVE-2026-23416 in the wild and no public exploit code.

Public exploit code:

- POC for CVE-2026-23416 (linux kernel 6.17 – linux kernel 7 rc5) - vulnerability discovered by Antonius (github_poc): https://github.com/bluedragonsecurity/CVE-2026-23416-POC

## 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-2026-23416 and fix it if it is affected.

What it is: CVE-2026-23416 is a medium-severity vulnerability in Linux kernel, published on 2 Apr 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-2026-23416 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-2026-23416/ (Markdown: https://insights.sbomify.com/CVE-2026-23416/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23416
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23416
- OSV: https://osv.dev/vulnerability/CVE-2026-23416

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23416/
Summaries are generated and may contain mistakes; the official description above is the record.