# CVE-2026-107169: M17n-lib: null-pointer write in read_mtext_element() on malformed utf-8

> An attacker can cause a denial of service by providing malformed UTF-8 input to the M17n-lib library, triggering a null pointer dereference crash.

- **Severity:** Medium 6.2 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Oct 2026
- **Updated:** 10 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-107169, GHSA-pjw2-cc43-prpf, UBUNTU-CVE-2026-107169

## What is CVE-2026-107169?

CVE-2026-107169 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 7 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in m17n-lib. An attacker could provide specially crafted or truncated UTF-8 input to trigger an unhandled null pointer dereference during text processing. This issue causes the application to crash unexpectedly, resulting in a Denial of Service (DoS).

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-107169?


## How do I fix CVE-2026-107169?

No fix has been published for CVE-2026-107169 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-107169 being exploited?

There is no known exploitation of CVE-2026-107169 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107169 and fix it if it is affected.

What it is: CVE-2026-107169 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 7 Oct 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-2026-107169 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. 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-2026-107169/ (Markdown: https://insights.sbomify.com/CVE-2026-107169/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107169
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107169
- OSV: https://osv.dev/vulnerability/CVE-2026-107169

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107169/
Summaries are generated and may contain mistakes; the official description above is the record.