Vulnerability · Published Sep 10, 2026 · Assigned by mongodb
CVE-2026-88035Heap buffer overflow via wrapped size check during SASL username canonicalization in MongoDB C Driver
Medium 4.7
In plain English
A medium-severity integer overflow in C Driver from MongoDB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | mongo-c-driver | 1.30.14-r0 | ALPINE-CVE-2026-88035 |
| Debian:12 | mongo-c-driver | no fix listed | DEBIAN-CVE-2026-88035 |
| Debian:13 | mongo-c-driver | no fix listed | DEBIAN-CVE-2026-88035 |
| Debian:14 | mongo-c-driver | 2.5.3-1 | DEBIAN-CVE-2026-88035 |
Affected products (as reported)
Weakness: CWE-190 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H