Vulnerability in MongoDB Libmongocrypt

CVE-2026-84962

An unauthorized user with key vault write access may cause an authorized client to issue arbitrary authenticated Google Cloud KMS API calls under the authorized user's identity, escalating database-level access into cloud key control and defeating client-side encryption.

Vulnerability class: CRLF Injection

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.2 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.002 (7.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 7.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-84962: held from 0.001 to 0.002.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-84962?
CVE-2026-84962 is a medium-severity vulnerability in MongoDB Libmongocrypt, classified under CRLF Injection. CVSS score: 4.2/10. Published 2026-09-03.
How severe is CVE-2026-84962?
Medium severity. CVSS v3 base score is 4.2 out of 10.