CVE-2026-90979
Apache Karaf: LDAP filter injection in JAAS LDAP login modules
Description
LDAPCache and LDAPBackingEngine build LDAP search filters for user lookup and role lookup by textually substituting the placeholders %u, %dn, and %fqdn (drawn from the login name, the resolved user DN, and its fully qualified namespace form) into administrator-configured filter templates (userFilter, roleFilter). Before the fix, the only sanitization applied to the substituted value was double backslashed: filter = filter.replaceAll(Pattern.quote("%u"), Matcher.quoteReplacement(user)); filter = filter.replace("\\", "\\\\"); This does not escape the other characters RFC 4515 requires escaping in an LDAP search filter: *, (, ), and NUL. A login name containing any of these can change the structure of the resulting filter rather than being matched as a literal value (e.g. a crafted username can turn an equality match into a wildcard match, or close/reopen filter clauses), widening what the search returns and potentially causing a login or role lookup to match an LDAP entry other than the intended one, over-granting roles, and depending on deployment-specific filter templates, potentially affecting which account a login resolved to. It's not exploitable through every entry points: LDAPLoginModule and LDAPPubkeyLoginModule both called Util.doRFC2254Encoding() (correct RFC 4515 escaping) on the login name before handing it to LDAPCache, which masked the missing escaping in LDAPCache for those two call paths. Using LDAPCache directly (bypassing the login modules) does not reproduce through the normal LDAPLoginModule/LDAPPubkeyLoginModule authentication flow for this reason. It does reproduce through two other call paths that reach LDAPCache/LDAPBackingEngine without any prior escaping: * GSSAPILdapLoginModule passes the NameCallback name straight through, unescaped. * LDAPBackingEngine (listRoles) passes principal.getName() straight through, unescaped.
INFO
Published Date :
Sept. 28, 2026, 10:16 a.m.
Last Modified :
Sept. 28, 2026, 10:16 a.m.
Remotely Exploit :
No
Source :
[email protected]
Solution
- Apply RFC 4515 escaping to all LDAP filter substitutions.
- Validate and sanitize user-provided filter templates.
- Update affected LDAP login modules.
- Review configurations for direct LDAPCache usage.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-90979.
| URL | Resource |
|---|---|
| https://karaf.apache.org/security/cve-2026-90979.txt |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-90979 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-90979
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-90979 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-90979 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Sep. 28, 2026
Action Type Old Value New Value Added Description LDAPCache and LDAPBackingEngine build LDAP search filters for user lookup and role lookup by textually substituting the placeholders %u, %dn, and %fqdn (drawn from the login name, the resolved user DN, and its fully qualified namespace form) into administrator-configured filter templates (userFilter, roleFilter). Before the fix, the only sanitization applied to the substituted value was double backslashed: filter = filter.replaceAll(Pattern.quote("%u"), Matcher.quoteReplacement(user)); filter = filter.replace("\\", "\\\\"); This does not escape the other characters RFC 4515 requires escaping in an LDAP search filter: *, (, ), and NUL. A login name containing any of these can change the structure of the resulting filter rather than being matched as a literal value (e.g. a crafted username can turn an equality match into a wildcard match, or close/reopen filter clauses), widening what the search returns and potentially causing a login or role lookup to match an LDAP entry other than the intended one, over-granting roles, and depending on deployment-specific filter templates, potentially affecting which account a login resolved to. It's not exploitable through every entry points: LDAPLoginModule and LDAPPubkeyLoginModule both called Util.doRFC2254Encoding() (correct RFC 4515 escaping) on the login name before handing it to LDAPCache, which masked the missing escaping in LDAPCache for those two call paths. Using LDAPCache directly (bypassing the login modules) does not reproduce through the normal LDAPLoginModule/LDAPPubkeyLoginModule authentication flow for this reason. It does reproduce through two other call paths that reach LDAPCache/LDAPBackingEngine without any prior escaping: * GSSAPILdapLoginModule passes the NameCallback name straight through, unescaped. * LDAPBackingEngine (listRoles) passes principal.getName() straight through, unescaped. Added CWE CWE-90 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90979.json">CVE-2026-90979</a> Added Reference https://karaf.apache.org/security/cve-2026-90979.txt