CVE-2026-84969

Name	CVE-2026-84969
Description	A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
mongo-c-driver (PTS)	bookworm	1.23.1-1+deb12u3	vulnerable
	trixie	1.30.4-1+deb13u2	vulnerable
	forky	2.5.1-1	vulnerable
	sid	2.5.2-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
mongo-c-driver	source	(unstable)	2.5.2-1

Notes

[trixie] - mongo-c-driver <no-dsa> (Minor issue)
https://jira.mongodb.org/browse/CDRIVER-6410
Fixed by: https://github.com/mongodb/mongo-c-driver/commit/4229afa3bb4d0842edd5ee8da0f5143bd563e0bd (2.5.2)
Fixed by: https://github.com/mongodb/mongo-c-driver/commit/08d0cfaaf08a54d7e87a5e5fa8d38251bf0eeca6 (1.30.9)