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Fencer Intel
medium 4.2

CVE-2025-53021 json

Moodle Session Fixation allows unauthenticated users to hijack sessions via sesskey parameter

published last yr. modified 2mo ago also BIT-moodle-2025-53021 , EUVD-2025-19060 , GHSA-cgvv-3455-824j

cvss
4.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist moodle/moodle 4.0.0
  • bitnami moodle 4.1.10

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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-2025-53021 updated cvss 4.2

moodle: Moodle session fixation

  • 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
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
GitHub 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
OSV 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist moodle/moodle
>=3.0.0, <4.0.0
4.0.0
bitnami moodle
>=3.0.0, <4.1.10
4.1.10

Affected products

  • Moodle Moodle

Classification

Weakness

References

Sources

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