What is CVE-2026-106434?

CVE-2026-106434 is a medium-severity vulnerability in MongoDB Libmongocrypt, classified under Improper Validation of Integrity Check Value. CVSS score: 4.3/10. Published 2026-10-08.

How severe is CVE-2026-106434?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in MongoDB Libmongocrypt

CVE-2026-106434

The explicit decryption component of MongoDB libmongocrypt can return an unrecognized encrypted payload unchanged instead of returning a decryption error. An actor who can modify stored encrypted fields, such as a database writer, server, or network intermediary, can cause an affected application to process the supplied bytes as decrypted plaintext.

Published 2026-10-08 · last modified 2026-10-08.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

MongoDB Libmongocrypt

Weakness classification (CWE)

CWE-354 — Improper Validation of Integrity Check Value

References

jira.mongodb.org/browse/MONGOCRYPT-966

Frequently asked questions

What is CVE-2026-106434?: CVE-2026-106434 is a medium-severity vulnerability in MongoDB Libmongocrypt, classified under Improper Validation of Integrity Check Value. CVSS score: 4.3/10. Published 2026-10-08.
How severe is CVE-2026-106434?: Medium severity. CVSS v3 base score is 4.3 out of 10.