OpenDJ Denial of Service (DoS) using alias loop

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2025-27497: 0.39% estimated exploitation activity in the next 30 days; percentile 33.13 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A denial-of-service (DoS) vulnerability in OpenDJ has been discovered that causes the server to become unresponsive to all LDAP requests without crashing or restarting. This issue occurs when an alias loop exists in the LDAP database. If an ldapsearch request is executed with alias dereferencing set to "always" on this alias entry, the server stops responding to all future requests. I have confirmed this issue using the latest OpenDJ version (9.2), both with the official OpenDJ Docker image and a local OpenDJ server running on my Windows 10 machine. Details An unauthenticated attacker can exploit this vulnerability using a single crafted ldapsearch request. Fortunately, the server can be restarted without data corruption. While this attack requires the existence of an alias loop, I am uncertain whether such loops can be easily created in specific environments or if the method can be adapted to execute other DoS attacks more easily. PoC (Steps to Reproduce) 1. Set up an OpenDJ…

Published by the source

5 Mar 2025, 18:33 UTC

Last modified by the source

5 Mar 2025, 18:33 UTC

Source last checked

26 Oct 2026, 16:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-93qr-h8pr-4593

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2025-27497

Advisory: OpenDJ Denial of Service (DoS) using alias loop
IDs: CVE-2025-27497, GHSA-93qr-h8pr-4593
Record: https://patchnext.com/advisories/cve-2025-27497 (revision 1, source checked 26 Oct 2026, 16:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.openidentityplatform.opendj:opendj-server-legacy 4.9.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.openidentityplatform.opendj:opendj-server-legacy: affected < 4.9.3; fixed in 4.9.3

## Suggested inspection (read-only)
- Maven org.openidentityplatform.opendj:opendj-server-legacy: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.openidentityplatform.opendj:opendj-server-legacy.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-93qr-h8pr-4593 (GitHub-reviewed advisory GHSA-93qr-h8pr-4593 lists affected ranges: Maven org.openidentityplatform.opendj:opendj-server-legacy >=0 <4.9.3)

Commands are suggestions: review each one before running it.