CVE-2026-88035 Heap buffer overflow via wrapped size check during SASL username canonicalization in MongoDB C Driver
An integer overflow in the MongoDB C Driver allows a denial of service via heap buffer overflow when using optional SASL authentication.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-88035?
CVE-2026-88035 is a medium-severity vulnerability in MongoDB C Driver, published on 10 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A size check in the client-side authentication path of the MongoDB C Driver can wrap around, so an unusually large user-name value is accepted and copied past the end of a small buffer. A party able to set the driver's connection settings may cause the application that embeds the driver to terminate unexpectedly. Reaching this code requires a build in which the optional external SASL authentication backend is present and a connection configured to use it.
Weakness: CWE-190
Which versions are affected by CVE-2026-88035?
It affects 1 product.
Products include Mongodb C Driver.
How do I fix CVE-2026-88035?
Apply the vendor's patch.
Is CVE-2026-88035 being exploited?
There is no known exploitation of CVE-2026-88035 in the wild and no public exploit code.
Other vulnerabilities in MongoDB 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-2026-88035, GHSA-jgj9-g5rr-w8xg, UBUNTU-CVE-2026-88035.