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Fencer Intel
critical 9.1

CVE-2026-15747 json

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

published 3mo ago modified 16d ago also EUVD-2026-44067

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

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.

Patch / fix

  • SRI Mojolicious 9.48
  • libmojolicious-perl Debian 14 9.48+dfsg-1

debian advisories DEBIAN-CVE-2026-15747

  • perl-Mojolicious SLE Module for Package Hub 15 SP7 9.370.0-150700.3.3.1

suse advisories SUSE-SU-2026:4151-1

  • perl-Mojolicious openSUSE Leap 16.0 9.480.0-bp160.1.1
  • perl-Mojolicious openSUSE Tumbleweed 9.480.0-1.1

opensuse advisories openSUSE-SU-2026:21496-1openSUSE-SU-2026:11282-1

Is CVE-2026-15747 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-15747 updated cvss 6.8

Mojolicious: Mojolicious: Information disclosure via BREACH compression oracle

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
3mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

  • SRI Mojolicious

Classification

Weakness
  • CWE-204 Observable Response Discrepancy
  • CWE-352 Cross-Site Request Forgery

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.