# CVE-2026-116268: MIME::Field::ParamVal versions before 5.521 for Perl allow CPU exhaustion via unclosed comments in header parameters


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-116268, GHSA-cgxv-575f-wxjm, UBUNTU-CVE-2026-116268

## What is CVE-2026-116268?

CVE-2026-116268 is a vulnerability, published on 28 Oct 2026. 

### Official description

MIME::Field::ParamVal versions before 5.521 for Perl allow CPU exhaustion via unclosed comments in header parameters.

The comment pattern used to parse Content-Type and Content-Disposition parameters scans from each "(" to the next ")". In a field with no ")", every "(" scans to the end of the header and fails, so parsing takes time quadratic in the header length. The field is parsed again on each attribute lookup, several times per MIME entity.

A 40 KB header takes about 7 seconds to parse once.

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-116268?


## How do I fix CVE-2026-116268?

No fix has been published for CVE-2026-116268 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-116268 being exploited?

There is no known exploitation of CVE-2026-116268 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-116268 and fix it if it is affected.

What it is: CVE-2026-116268 is a vulnerability, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-116268 in the wild and no public exploit code.

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-2026-116268/ (Markdown: https://insights.sbomify.com/CVE-2026-116268/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-116268
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116268
- OSV: https://osv.dev/vulnerability/CVE-2026-116268

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-116268/
Summaries are generated and may contain mistakes; the official description above is the record.