OpenDJ: Authorization bypass in SASL PLAIN allowing a `proxied-auth` holder to impersonate any resolvable non-root user without an ACI proxy grant

published 2026-07-24 3 mo ago modified 2026-10-24 15 d ago also GHSA-p279-2cqp-84jg , EUVD-2026-58186

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits: 0; none known

OpenDJ is an LDAPv3 compliant directory service. Prior to 5.1.2, the SASL PLAIN authorization identity path in opendj-server-legacy/src/main/java/org/opends/server/extensions/PlainSASLMechanismHandler.java checked the PROXIED_AUTH privilege but did not evaluate the mayProxy proxy ACI scope when an authzid resolved to a different user. Both dn: and u: or bare authzid forms could therefore let an authenticated account holding PROXIED_AUTH assume any resolvable non-root identity outside the identities permitted by its proxy ACI. The fix returns INVALID_CREDENTIALS (49) before password verification when the target authorization identity is not permitted. This issue is fixed in version 5.1.2.

Patch / fix

fixed in 1 links 2

maven org.openidentityplatform.opendj:opendj-server-legacy 5.1.2

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 2 mo ago (2026-08-18)

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
GitHub	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
maven	org.openidentityplatform.opendj:opendj-server-legacy	<5.1.2	5.1.2

Affected products

OpenIdentityPlatform OpenDJ

Classification

Weakness

CWE-285 Improper Authorization
CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary