CVE-2026-15747: Sri Mojolicious

Critical severity, CVSS 9.1. EPSS: 0.3% chance of exploitation in the next 30 days.

Mojolicious versions from 4.59 before 9.48 for Perl expose a stable representation of the session CSRF token to a BREACH compression oracle. _csrf_token generates and caches one token per session and returns the same value on every call, and _csrf_field places that value in a hidden `csrf_token` input. When a response carrying the token also echoes attacker-controlled input and is gzip-compressed, the chosen values and the resulting compressed lengths form a BREACH oracle. An attacker able to query it can recover the token and pass csrf_protect validation.

Affected products

• Sri Mojolicious: from 4.59, before 9.48 (fixed in 9.48)

Published 2026-07-14. Last modified 2026-07-15.