CVE-2026-40458

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

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://cert.pl/en/posts/2026/04/CVE-2026-40458/	Third Party Advisory
https://www.pac4j.org/blog/security-advisory-pac4j-core-and-ldap.html	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:pac4j:pac4j::::::::
	cpe:2.3:a:pac4j:pac4j::::::::

History

20 Apr 2026, 14:41

Type	Values Removed	Values Added
First Time		Pac4j Pac4j pac4j
References	~~() https://cert.pl/en/posts/2026/04/CVE-2026-40458/ -~~	() https://cert.pl/en/posts/2026/04/CVE-2026-40458/ - Third Party Advisory
References	~~() https://www.pac4j.org/blog/security-advisory-pac4j-core-and-ldap.html -~~	() https://www.pac4j.org/blog/security-advisory-pac4j-core-and-ldap.html - Vendor Advisory
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 6.5
CPE		cpe:2.3:a:pac4j:pac4j::::::::

17 Apr 2026, 14:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-04-17 14:16

Updated : 2026-04-20 14:41

NVD link : CVE-2026-40458

Mitre link : CVE-2026-40458

CVE.ORG link : CVE-2026-40458

JSON object : View

Products Affected

pac4j

pac4j

CWE

CWE-352

Cross-Site Request Forgery (CSRF)

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