CVSS 4.0
7.5 highCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCVE-2026-120807 Privilege escalation via fail-open user lookup in X.509 cluster-membership guard
High (7.5) in mongodb mongodb server. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
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.
Severity
CVSS 3.1
6.6 mediumCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 14th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: PoC · Automatable: no · Technical impact: total, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-754 Improper Check for Unusual or Exceptional Conditions
- OWASP Top 10
- A10:2025 Mishandling of Exceptional Conditions
- Published
- Modified
- Assigned by
- mongodb (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
- mongodb:mongodb server
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| MongoDB Server | from 9.0.0 before 9.0.7 |
| MongoDB Server | from 8.3.0 before 8.3.16 |
| MongoDB Server | from 8.0.0 before 8.0.37 |
| MongoDB Server | from 7.0.0 before 7.0.48 |