Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:N) | Network: reachable remotely |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:N) | No attack requirements |
| Privileges required (PR:L) | Low privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:H) | High integrity impact |
| Availability (VA:H) | High availability impact |
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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
About Pac4j
CVE-2026-40459 affects Pac4j, a product from Pac4j. Before acting, confirm where Pac4j runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: 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
Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Pac4j |
| Affected versions | Pac4j from 4.0.0 before 4.5.10; Pac4j from 5.0.0 before 5.7.10; Pac4j from 6.0.0 before 6.4.1 |
| Published | Apr 17, 2026 |
| Last modified | Jun 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | cvd@cert.pl |
How to detect it
- Inventory every instance of Pac4j and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Pac4j named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Pac4j to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
Technical References
Frequently asked questions
Related CVEs
An LDAP injection vulnerability in the LDAP Certificate repository of the XKMS server in Apache CXF may allow an attacker to retrieve arbitrary certificates from the repository. Users are recommended to upgrade to versions 4.2.1, 4.1.6 or 3.6.11, which fix this issue.
SuiteCRM is an open-source, enterprise-ready Customer Relationship Management (CRM) software application. Prior to versions 7.15.1 and 8.9.3, an LDAP Injection vulnerability exists in the SuiteCRM authentication flow. The application fails to properly sanitize user-supplied input before embedding it into the LDAP search filter. By injecting LDAP control characters, an unauthenticated attacker can manipulate the query logic, which can lead to authentication bypass or information disclosure. Versions 7.15.1 and 8.9.3 patch the issue.
MISP is an open source threat intelligence and sharing platform. Prior to 2.5.36, improper neutralization of special elements in an LDAP query in ApacheAuthenticate.php allows LDAP injection via an unsanitized username value when ApacheAuthenticate.apacheEnv is configured to use a user-controlled server variable instead of REMOTE_USER (such as in certain proxy setups). An attacker able to control that value can manipulate the LDAP search filter and potentially bypass authentication constraints or cause unauthorized LDAP queries. This vulnerability is fixed in 2.5.36.
A remote attacker can inject LDAP special characters into the Distinguished Name (DN) construction in DefaultLdapRealm class. User-supplied username input is directly concatenated into the LDAP DN template without any escaping of RFC 2253 special characters. This allows an attacker to manipulate the DN structure used for LDAP bind authentication, potentially bypassing authentication or impersonating other users. This issue affects all Apache Shiro versions through 2.2.0, and 3.0.0-alpha-1 when using DefaultLdapRealm Upgrade to Apache Shiro 2.2.1 or 3.0.0-alpha-2 or later, which fixes the issue.
WeKan versions prior to 8.19 contain an LDAP filter injection vulnerability in LDAP authentication. User-supplied username input is incorporated into LDAP search filters and DN-related values without adequate escaping, allowing an attacker to manipulate LDAP queries during authentication.
Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection') vulnerability in Apache APISIX. A caller who holds valid credentials for one entry in the LDAP directory can authenticate through APISIX as a consumer mapped to a different entry, one the plugin's configured scope was meant to keep out of reach. This issue affects Apache APISIX: from 2.11.0 through 3.17.0. Users are recommended to upgrade to version 3.18.0, which fixes the issue.
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