CVE-2026-120807 (CVSS 6.6)

Description

A flaw in MongoDB’s X.509 cluster-membership authentication guard could allow a holder of a cluster-member certificate to gain elevated internal privileges when a specific deployment configuration is in use. An internal check, which prevents a certificate recognized as a cluster member from also being treated as a regular user, does not correctly distinguish between certain error conditions encountered during user lookup. Under certain timing conditions, this can cause the check to be bypassed, granting the connection full internal system privileges. Triggering this issue requires possession of a valid cluster-member TLS certificate, non-default X.509 cluster authentication configuration, and specific conditions during the user cache lookup process.

Is your site exposed to CVE-2026-120807?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

6.6

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.14%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-754 CWE-754

References

Other References

https://jira.mongodb.org/browse/SERVER-130169

Frequently Asked Questions

What is CVE-2026-120807? +

A flaw in MongoDB’s X.509 cluster-membership authentication guard could allow a holder of a cluster-member certificate to gain elevated internal privileges when a specific deployment configuration is in use. An internal check, which prevents a certificate recognized as a cluster member from also being treated as a regular user, does not correctly distinguish between certain error conditions encountered during user lookup. Under certain timing conditions, this can cause the check to be bypassed, granting the connection full internal system privileges. Triggering this issue requires possession of a valid cluster-member TLS certificate, non-default X.509 cluster authentication configuration, and specific conditions during the user cache lookup process. It has a CVSS v3.1 base score of 6.6 (MEDIUM).

How severe is CVE-2026-120807? +

CVE-2026-120807 has a CVSS v3.1 score of 6.6 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-120807? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-0317

A denial of service vulnerability in Palo Alto Networks PAN-OS software enables an authenticated user with a read-only administrator role …

CVE-2026-0667

CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability that could cause arbitrary code execution, denial of service and loss …

CVE-2026-35225

An unauthenticated remote attacker is able to exhaust all available TCP connections in the CODESYS EtherNet/IP adapter stack, preventing legitimate …

CVE-2025-0112

A problem with a detection mechanism in the Palo Alto Networks Cortex XDR agent on Windows devices enables a user …

CVE-2025-0116

A Denial of Service (DoS) vulnerability in Palo Alto Networks PAN-OS software causes the firewall to unexpectedly reboot when processing …

CVE-2025-0128

A denial-of-service (DoS) vulnerability in the Simple Certificate Enrollment Protocol (SCEP) authentication feature of Palo Alto Networks PAN-OS® software enables …