CVE-2026-40459

Q: How do I fix CVE-2026-40459?

Upgrade pac4j to 6.4.1 or later.

Q: Is CVE-2026-40459 being actively exploited?

Not that we know of. CVE-2026-40459 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.61% is the estimated probability that it will be exploited in the next 30 days. That is higher than 46% of all scored CVEs.

Q: How severe is CVE-2026-40459?

CVE-2026-40459 has a CVSS v3 base score of 8.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-40459 affect?

Published advisories record a fix for pac4j (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

HIGH

8.8

CVSS v3

NVD

Description

PAC4J is vulnerable to LDAP Injection in multiple methods. A low-privileged remote attacker can inject crafted LDAP syntax into ID-based search parameters, potentially resulting in unauthorized LDAP queries and arbitrary directory operations. This issue was fixed in PAC4J versions 4.5.10, 5.7.10 and 6.4.1

CWE-90

How to fix

Remediation Available

pac4jNVD

Affected:>= 6.0.0, < 6.4.1Fixed in:6.4.1CVE-2026-40459derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.61%probability of exploitation in 30 days

46thpercentile

Moderate risk: more likely to be exploited than 46% of all known CVEs.

References

Vendor Advisory1

pac4j.org

Third-Party Advisory1

cert.pl

Related Vulnerabilities

Other CWE-90 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2016-9299	Critical	9.8	97%	-	-
CVE-2017-14596	Critical	9.8	6.9%	-	-
CVE-2016-8750	Medium	6.5	5.2%	-	Fix
CVE-2021-43350	Critical	9.8	4.4%	-	Fix
CVE-2017-4927	High	7.5	2.3%	-	Fix
CVE-2024-27310	Medium	5.3	2.3%	-	Fix

Common questions

How do I fix CVE-2026-40459?

Upgrade pac4j to 6.4.1 or later.

Is CVE-2026-40459 being actively exploited?

Not that we know of. CVE-2026-40459 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.61% is the estimated probability that it will be exploited in the next 30 days. That is higher than 46% of all scored CVEs.

How severe is CVE-2026-40459?

CVE-2026-40459 has a CVSS v3 base score of 8.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-40459 affect?

Published advisories record a fix for pac4j (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-20.