# CVE-2026-116738: VMime through 0.9.2 Stack-Based Buffer Overflow via uuencode Decoder


- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 26 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-116738, GHSA-rhj9-fcgr-5r62

## What is CVE-2026-116738?

CVE-2026-116738 is a high-severity vulnerability in kisli vmime, published on 26 Oct 2026. 

### Official description

VMime through 0.9.2 contains an integer underflow in the uuEncoder::decode function that allows remote attackers to trigger a stack-based buffer overflow via crafted uuencoded MIME parts. Attackers can send an email with a uuencoded line whose length character is 'b' but is not a 'begin' line, corrupting stack memory to crash the application or potentially execute code.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-116738?


## How do I fix CVE-2026-116738?

No fix has been published for CVE-2026-116738 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-116738 being exploited?

There is no known exploitation of CVE-2026-116738 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-116738 and fix it if it is affected.

What it is: CVE-2026-116738 is a high-severity vulnerability in kisli vmime, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-116738 in the wild and no public exploit code.

Affected product: kisli vmime. 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-2026-116738/ (Markdown: https://insights.sbomify.com/CVE-2026-116738/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-116738
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116738
- OSV: https://osv.dev/vulnerability/CVE-2026-116738

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-116738/
Summaries are generated and may contain mistakes; the official description above is the record.