CVE-2026-40458
mediumpriority · track · 26EPSS 0.002 · 6 %ileEUFRUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.7–7
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
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affected products (7)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- GHSA-xw5c-jc7x-gf75PAC4J has a Cross-Site Request Forgery (CSRF) Vulnerability2026-04-17ghsa · osvUS
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.
- CERTFR-2026-AVI-1336Multiples vulnérabilités dans les produits IBMFrançais2026-10-16vendor · certfrFR
also known as (2)
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sources
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references (6)
External citations — patches, advisories, analysis.
- https://nvd.nist.gov/vuln/detail/CVE-2026-40458cnnvd
- https://www.pac4j.org/Patchcnnvd
- https://cert.pl/en/posts/2026/04/CVE-2026-40458/enisa_euvd
- https://www.pac4j.org/blog/security-advisory-pac4j-core-and-ldap.htmlenisa_euvd
- https://cert.pl/en/posts/2026/04/CVE-2026-40458/Third Party Advisorynvd
- https://www.pac4j.org/blog/security-advisory-pac4j-core-and-ldap.htmlVendor Advisorynvd
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