CVE-2026-6231 bson_validate may skip validation when processing certain inputs
The MongoDB C Driver may incorrectly validate BSON data, allowing malformed inputs to bypass checks and potentially cause downstream processing errors.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-6231?
CVE-2026-6231 is a medium-severity vulnerability in MongoDB Inc. C Driver, published on 13 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The bson_validate function may return early on specific inputs and incorrectly report success. This behavior could result in skipping validation for BSON data, allowing malformed or invalid UTF-8 sequences to bypass validation and be processed incorrectly. The issue may affect applications that rely on these functions to validate untrusted BSON data before further processing. This issue affects MongoDB C Driver versions prior to 1.30.5, MongoDB C Driver version 2.0.0 and MongoDB C Driver version 2.0.1
Weakness: CWE-20
Which versions are affected by CVE-2026-6231?
It affects 1 product.
Products include Mongodb C Driver.
How do I fix CVE-2026-6231?
Upgrade to a fixed version.
Is CVE-2026-6231 being exploited?
There is no known exploitation of CVE-2026-6231 in the wild and no public exploit code.
Other vulnerabilities in MongoDB Inc. C Driver
- CVE-2026-93393 Heap overflow via oversized decrypted TLS record sequence in Windows Secure Channel stream
- CVE-2026-6691 MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow
- CVE-2026-84964 Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client
- CVE-2024-7553 Accessing Untrusted Directory May Allow Local Privilege Escalation
- CVE-2026-93395 Integer Underflow → Heap Out-of-Bounds Read in `bson_new_from_buffer()
Sources
Also known as DEBIAN-CVE-2026-6231, GHSA-q869-m422-4qcv, JLSEC-2026-773, UBUNTU-CVE-2026-6231.