CVE-2026-90979

CVE-2026-90979 is a high-severity vulnerability with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-90.

Key facts

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.

Frequently asked questions

What is CVE-2026-90979?
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.
How severe is CVE-2026-90979?
CVE-2026-90979 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-90979 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-90979?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-90979 published?
CVE-2026-90979 was published on 2026-09-28 and last updated on 2026-09-30.

References

Other CWE-90 (LDAP Injection) vulnerabilities

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