svg-sanitizer before 1.1.0 Quadratic CPU-Exhaustion DoS via PHP-Tag Stripping Loop

Summary

svg-sanitizer from 0.5.3 before 1.1.0 contains a denial of service vulnerability in Sanitizer::sanitize() that repeatedly rescans the whole input while stripping PHP tags. Unauthenticated attackers can upload SVGs with many overlapping PHP tag openers and closers, forcing quadratic preg_replace passes that exhaust worker CPU for minutes.

Remediation

1. Inventory every darylldoyle svg-sanitizer deployment, including staging.
2. Upgrade darylldoyle svg-sanitizer to 1.1.0.
3. Confirm the running version after the upgrade.

References

• Patchhttps://github.com/darylldoyle/svg-sanitizer/commit/9ba9001493f5da737759303f13bd965ebdaa778c
• Advisoryhttps://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-2v7c-jx29-jprp
• Advisoryhttps://www.vulncheck.com/advisories/svg-sanitizer-before-1.1.0-quadratic-cpu-exhaustion-dos-via-php-tag-stripping-loop