CVE-2026-40458
PAC4J is vulnerable to Cross-Site Request Forgery (CSRF).
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- CVSS 4.0
- 7.0 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.17% probability · 6th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-352
- Affected
- pac4j/pac4j
- Source
- cvd@cert.pl
References
- https://cert.pl/en/posts/2026/04/CVE-2026-40458/Third Party Advisory
- https://www.pac4j.org/blog/security-advisory-pac4j-core-and-ldap.htmlVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.