# CVE-2026-121637: WatchGuard AuthPoint Gateway improper HMAC validation in LDAP authentication

Source: https://junglewise.ai/threats/cve-2026-121637-an-improper-integrity-validation-vulnerability-in-watchguard  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-04. Updated: 2026-11-04  
License: CC BY 4.0 with a link back

CVE-2026-121637 · Severity: info · Published 2026-11-04

WatchGuard AuthPoint Gateway is an authentication service that validates user credentials against LDAP directories. An attacker who obtains a valid signature can forge authentication results and session identifiers, potentially gaining unauthorized access to protected systems without valid credentials.

Technologies: [Watchguard AuthPoint Authentication Gateway](https://junglewise.ai/threats/technologies/authpoint-authentication-gateway). Vendors: [Watchguard](https://junglewise.ai/threats/vendors/watchguard).

## Quick answers

**Is CVE-2026-121637 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121637 being exploited in the wild.

**How severe is CVE-2026-121637?** Informational severity, published 4 November 2026.

**Which products and versions are affected?** Watchguard AuthPoint Authentication Gateway 1.0 to 7.5.x (versions before 7.6.0).

**Is there a fix for CVE-2026-121637?** Yes: fixed in AuthPoint Authentication Gateway 7.6.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-121637 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-121637?** Check whether you run Watchguard AuthPoint Authentication Gateway at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in AuthPoint Authentication Gateway 7.6.0

## Technical details

An improper integrity validation flaw in the LDAP authentication callback handler fails to fully validate HMAC signatures, allowing a network attacker to forge the authentication result and transaction identifier in the request body if they have obtained a valid header signature. This enables session hijacking and bypassing authentication controls. A fix is available in AuthPoint Authentication Gateway 7.6.0.

## Affected products

- WatchGuard AuthPoint Authentication Gateway 1.0 to 7.5.x (versions before 7.6.0)

## Timeline

- 2026-11-04: disclosed
- other: Vendor states no known exploitation in the wild

## References

- [https://psirt.watchguard.com/CVE-2026-121637](https://psirt.watchguard.com/CVE-2026-121637)

## Related threats

- [WatchGuard AuthPoint Gateway authentication bypass by capture-replay](https://junglewise.ai/threats/cve-2026-121640-an-authentication-bypass-by-capture-replay-vulnerability-in)
- [WatchGuard AuthPoint Gateway authentication bypass](https://junglewise.ai/threats/cve-2026-121639-a-missing-authentication-for-critical-function-vulnerability-in)
- [WatchGuard AuthPoint Gateway improper certificate validation](https://junglewise.ai/threats/cve-2026-121638-an-improper-certificate-validation-vulnerability-in-watchguard)
- [WatchGuard AuthPoint Gateway authentication bypass in LDAP Sync](https://junglewise.ai/threats/cve-2026-95676-a-missing-improper-authentication-vulnerability-in-the-watchguard)