Cross-Site Request Forgery in PAC4J_CVE-2026-40458

7 / 10

HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

Description

PAC4J is vulnerable to Cross-Site Request Forgery (CSRF). A malicious attacker can craft a specially designed website which, when visited by a user, will automatically submit a forged cross-site request with a token whose hash collides with the victim's legitimate CSRF token. Importantly, the attacker does not need to know the victim’s CSRF token or its hash prior to the attack. Collisions in the deterministic String.hashCode() function can be computed directly, reducing the effective token's security space to 32 bits. This bypasses CSRF protection, allowing profile updates, password changes, account linking, and any other state-changing operations to be performed without the victim's consent.

This issue was fixed in PAC4J versions 5.7.10 and 6.4.1

Basic Information

ID CVE-2026-40458

Source CERT-PL

Published Apr 17, 2026 at 13:18

Affected Product

Vendor PAC4J

Product PAC4J

Version 5.0

Affected Versions PAC4J PAC4J 5.0
PAC4J PAC4J 6.0

CWE Classification

CWE-352

References

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    "published": "2026-04-17T13:18:26.308Z",
    "modified": "2026-04-17T13:18:26.308Z",
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