Session Fixation in Wikimedia OAuth

Publication date: 2026-07-01

Last updated on: 2026-07-13

Assigner: wikimedia-foundation

Description

Session fixation vulnerability in Wikimedia Foundation OAuth. This vulnerability is associated with program files src/Backend/MWOAuthServer.Php. This issue affects OAuth: from * through 1.46.0, 1.45.4, 1.44.6, 1.43.9.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-07-01

Last Modified

2026-07-13

Generated

2026-07-21

AI Q&A

2026-07-01

EPSS Evaluated

2026-07-20

NVD

CVE-2026-13707

EUVD

EUVD-2026-41033

Affected Vendors & Products

Vendor	Product	Version / Range
mediawiki	mediawiki	From 1.44.0 (inc) to 1.44.6 (exc)
mediawiki	mediawiki	From 1.45.0 (inc) to 1.45.4 (exc)
mediawiki	mediawiki	From 1.43.0 (inc) to 1.43.9 (exc)
mediawiki	mediawiki	1.46.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-384	Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.

Attack-Flow Graph

Executive Summary

This vulnerability is a session fixation issue found in the Wikimedia Foundation OAuth implementation. It affects certain versions of the OAuth program files, specifically src/Backend/MWOAuthServer.Php. Session fixation vulnerabilities allow an attacker to fixate a user's session ID before the user logs in, potentially enabling the attacker to hijack the user's authenticated session.

Impact Analysis

The session fixation vulnerability can allow an attacker to hijack a user's session by forcing a known session ID. This can lead to unauthorized access to the user's account or actions performed on their behalf, compromising the security and privacy of the affected user.

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