Heap-based buffer overflow in MongoDB driver for C - CVE-2026-84969

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Main Vulnerability Database Vulnerabilities #VU147243

Heap-based buffer overflow in MongoDB driver for C - CVE-2026-84969

Published: September 7, 2026


Vulnerability identifier: #VU147243
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-84969
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to alter data outside the intended buffer.

The vulnerability exists due to a heap-based buffer overflow in the BSON-to-JSON conversion helpers when encoding a binary field in output cut short at a caller-configured length limit. A remote attacker can supply a document containing a binary field to alter data outside the intended buffer.


Affected software

MongoDB driver for C
Fedora
mongo-c-driver

How to mitigate CVE-2026-84969

Install security update from vendor's website.

MongoDB driver for C - addressed in versions 1.30.9, 2.5.2
mongo-c-driver - addressed in versions 1.30.9-1.el8, 1.30.9-1.el9, 1.30.9-1.el10_2, 1.30.9-1.fc43, 1.30.9-1.fc44, 2.5.2-1.el10_3, 2.5.2-1.el10_4, 2.5.2-1.fc45

External References

Related Security Bulletins