What is CVE-2026-121637?
An improper integrity validation vulnerability in WatchGuard AuthPoint Gateway's LDAP authentication callback allows a network attacker who has obtained a valid header signature to forge the authentication result and transaction identifier in the request body, resulting in unauthorized session outcomes.
The record classifies CVE-2026-121637 under weakness class CWE-345. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 2 days ago.
Severity and exploitation probability
- CVSS v4.0 base score
- 8.9 — High (derived from score)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N - EPSS (FIRST)
- 0.2% probability of exploitation in the next 30 days, higher than 18.4% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-11-04
Is CVE-2026-121637 being exploited?
It currently carries a trending score of 39 in the Threadlinqs vulnerability feed.
Affected products and versions
- WatchGuard: AuthPoint Authentication Gateway
How to fix CVE-2026-121637
Vendor advisory: https://psirt.watchguard.com/CVE-2026-121637. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-121637
1 tracked threat in the Threadlinqs corpus references CVE-2026-121637, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.