CVE-2026-40458
Severity CVSS v4.0:
HIGH
Type:
CWE-352
Cross-Site Request Forgery (CSRF)
Publication date:
17/04/2026
Last modified:
20/04/2026
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&#39;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&#39;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&#39;s consent.<br />
<br />
This issue was fixed in PAC4J versions 5.7.10 and 6.4.1
Impact
Base Score 4.0
7.00
Severity 4.0
HIGH
Base Score 3.x
6.50
Severity 3.x
MEDIUM
Vulnerable products and versions
| CPE | From | Up to |
|---|---|---|
| cpe:2.3:a:pac4j:pac4j:*:*:*:*:*:*:*:* | 5.0.0 (including) | 5.7.10 (excluding) |
| cpe:2.3:a:pac4j:pac4j:*:*:*:*:*:*:*:* | 6.0.0 (excluding) | 6.4.1 (excluding) |
To consult the complete list of CPE names with products and versions, see this page