What is CVE-2026-106438?

CVE-2026-106438 is a medium-severity vulnerability in MongoDB C Driver, classified under Incorrect Calculation. CVSS score: 4.0/10. Published 2026-10-08.

How severe is CVE-2026-106438?

Medium severity. CVSS v3 base score is 4.0 out of 10.

Vulnerability in MongoDB C Driver

CVE-2026-106438

An incorrect calculation in Decimal128 string parsing in the MongoDB C Driver can accept certain over-precision inputs containing leading zeros instead of rejecting them. This produces a value different from the supplied text. An actor who can provide a decimal string to an embedding application, including through Extended JSON parsing, can cause the application to store or use an incorrect numeric value.

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

CVSS v3 metric

CVSS v3 base score 4.0 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/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 C Driver

Weakness classification (CWE)

CWE-682 — Incorrect Calculation

References

jira.mongodb.org/browse/CDRIVER-6419

Frequently asked questions

What is CVE-2026-106438?: CVE-2026-106438 is a medium-severity vulnerability in MongoDB C Driver, classified under Incorrect Calculation. CVSS score: 4.0/10. Published 2026-10-08.
How severe is CVE-2026-106438?: Medium severity. CVSS v3 base score is 4.0 out of 10.