8.7

CVE-2026-81518: mongodb bi_connector Improper Certificate Validation

CVSS: 8.7v4.0HighAnalyzed
Published 28-08-2026Last modified 31-08-2026
Open JSON

Vulnerability summary

CVE-2026-81518 is a high (CVSS 8.7) Improper Certificate Validation vulnerability in mongodb bi_connector. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.8% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.25%
0%100%
Low · +0.10 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 28-08-2026
    PublishedVulnerability first disclosed.
  2. 31-08-2026
    Last modifiedVulnerability information updated.

Description

When mongosqld is configured with a client certificate authority file, the listener requests a client certificate during the TLS handshake but does not require one, so a client that presents no certificate is still accepted. In deployments that rely on client certificates as the sole means of identifying users, a remote party with network access to the listener can therefore establish a session and read the MongoDB data exposed through the connector.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.25%

Chance of exploitation in the next 30 days

Percentile

16%

Versus all other CVEs

30-day change

+0.10 pp

From 0.15% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.25%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Mongodb1 product

1 vendor · 1 product

References

1 links