CVE-2026-40458
Cross-Site Request Forgery in PAC4J
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
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Active
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
7.0
Cross-Site Request Forgery in PAC4J
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
- Record
CVE-2026-40458- CVSS 4.0
- 7.0 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 - Weakness
- CWE-352
- Updated
- 2026-11-02
EUVDEUVD-2026-23421
7.0
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
- Record
EUVD-2026-23421- CVSS 4.0
- 7.0 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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-xw5c-jc7x-gf75
7.0
PAC4J has a Cross-Site Request Forgery (CSRF) Vulnerability
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.
- Record
GHSA-xw5c-jc7x-gf75- CVSS 4.0
- 7.0 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 - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N - Weakness
- CWE-352
- Updated
- 2026-11-02
NVD
7.0
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
- Record
CVE-2026-40458- CVSS 4.0
- 7.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N - Weakness
- CWE-352
- Updated
- 2026-11-02
OSV
7.0
Cross-Site Request Forgery in PAC4J
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
- Record
CVE-2026-40458- CVSS 4.0
- 7.0 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 - Weakness
- CWE-352
- Updated
- 2026-11-02
OSVGHSA-xw5c-jc7x-gf75
7.0
PAC4J has a Cross-Site Request Forgery (CSRF) Vulnerability
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.
- Record
GHSA-xw5c-jc7x-gf75- CVSS 4.0
- 7.0 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 - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N - Weakness
- CWE-352
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.pac4j:pac4j-coreMaven |
before 5.7.10 | 5.7.10 |
org.pac4j:pac4j-coreMaven |
6.0.0-RC1 up to 6.4.1 | 6.4.1 |
org.pac4j:pac4j-coreMaven |
before 5.7.10, plus listed versions 1.4.01.4.11.5.01.5.11.6.0 Show 45 moreShow less1.6.0-RC11.7.01.7.11.7.21.8.01.8.0-RC11.8.11.8.21.8.31.8.41.8.51.8.61.8.71.8.81.8.91.9.01.9.11.9.21.9.31.9.41.9.51.9.61.9.71.9.81.9.92.0.02.0.0-RC12.0.0-RC22.1.02.2.02.2.12.3.02.3.13.0.03.0.0-RC13.0.0-RC23.0.13.0.23.1.03.2.03.3.03.4.03.5.03.6.03.6.1 |
5.7.10 |
org.pac4j:pac4j-coreMaven |
6.0.0-RC1 up to 6.4.1, plus listed versions 6.0.06.0.0-RC106.0.0-RC26.0.0-RC36.0.0-RC4 Show 25 moreShow less6.0.0-RC56.0.0-RC66.0.0-RC76.0.0-RC86.0.0-RC96.0.16.0.26.0.36.0.46.0.4.16.0.56.0.66.1.06.1.16.1.26.1.36.2.06.2.16.2.26.3.06.3.16.3.26.3.36.4.06.4.0-RC1 |
6.4.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-40458 is a high vulnerability (CVSS 7.0) in Pac4j, published April 17, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.17%, the 5th percentile. Fixed in org.pac4j:pac4j-core 5.7.10.
References
Left out here: 63 versions. The JSON record has them.