CVE-2026-120807: Privilege escalation via fail-open user lookup in X.509 cluster-membership guard
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-11 15:49 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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.
Description quoted from the CVE record (assigned by mongodb, published 2026-11-10).
Weakness: CWE-754: Improper Check for Unusual or Exceptional Conditions
How it can be exploited
Exploitable over the network with high attack complexity only when specific conditions are present needing high privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Public exploit evidence (Exploit Observer)
Exploit Observer has no public exploit code naming this CVE. Check Exploit Observer for anything new.
Live scores
- EPSS
- 0.002
low predicted chance of attack - VEDAS
- 0.047
little exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| MongoDB Server | from 9.0.0 before 9.0.7 from 8.3.0 before 8.3.16 from 8.0.0 before 8.0.37 from 7.0.0 before 7.0.48 | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
Fixed versions stated in the CVE record: 9.0.7, 8.3.16, 8.0.37, 7.0.48.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
Advisories on this CVE
References
Other references
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
Supporting partners
