VulnerabilityAnalyzed

CVE-2025-53021

A session fixation vulnerability in Moodle 3.x through 3.11.18 allows unauthenticated attackers to hijack user sessions via the sesskey parameter.

MEDIUM 4.2EPSS 0.29%

Does this matter?

Lower severity and a low EPSS score (0.29%). Track it; it rarely justifies an emergency change on its own.

Description

A session fixation vulnerability in Moodle 3.x through 3.11.18 allows unauthenticated attackers to hijack user sessions via the sesskey parameter. The sesskey can be obtained without authentication and reused within the OAuth2 login flow, resulting in the victim's session being linked to the attacker's. Successful exploitation results in full account takeover. According to the Moodle Releases page, "Bug fixes for security issues in 3.11.x ended 11 December 2023." NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

CVSS 3.1: 4.2 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS: 0.29% probability · 22th percentile
CISA KEV: Not listed
Weakness: CWE-384
Affected: moodle/moodle
Source: cve@mitre.org

References

https://github.com/moodle/moodle/releases/tag/v3.11.18Product
https://moodledev.io/general/releases#moodle-311Product
https://rentry.co/moodle-oauth2-cveThird Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.