Paper/Archive/CVE-2026-15747

CVE-2026-15747

SRI Mojolicious — Mojolicious versions from 4.59 before 9.48 for Perl expose a stable representation of the session CSRF token to a BREACH compression oracle

EPSS 0.3%CVSS 9.1

critical.is priorityof 100

CVSS 9.1 (ADP)9.1 / 10 × 3027.3 Not in CISA KEV+300.0 EPSS percentile 16.4.164 × 203.3 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the CVE record

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

ProductAffectedFixed inSource

Mojolicious4.59 – < 9.489.48CNA

Scores by source

CISA ADP9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

patchgithub.com/mojolicious/mojo/commit/01921fbbbbeca2d1397e082d4a647f9b84c24e27.patch refmetacpan.org/release/SRI/Mojolicious-9.48/changes refopenwall.com/lists/oss-security/2026/07/14/16