CVE-2026-54696

Name	CVE-2026-54696
Description	Ruby JSON is a JSON implementation for Ruby. Versions 2.9.0 through 2.19.8 are vulnerable to heap buffer overflow when the JSON generator is provided with an oversized streamed object. When streaming to an IO JSON.dump(obj, io) and JSON::State#generate(obj, io) can write past the internal JSON generator buffer when a streamed object contains an attacker-controlled string near 16 KB. Exploitation would result in a reliable process crash/denial of service. This issue has been fixed in version 2.19.9.
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
ruby-json (PTS)	bullseye	2.3.0+dfsg-1	fixed
	bookworm	2.6.3+dfsg-1	fixed
	trixie	2.9.1+dfsg-1	vulnerable
	forky, sid	2.21.1+dfsg-1	fixed

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

Package	Type	Release	Fixed Version
ruby-json	source	bullseye	(not affected)
ruby-json	source	bookworm	(not affected)
ruby-json	source	(unstable)	2.19.9+dfsg-1

Notes

[trixie] - ruby-json <no-dsa> (Minor issue)
[bookworm] - ruby-json <not-affected> (Vulnerable code introduced in 2.9.0)
[bullseye] - ruby-json <not-affected> (Vulnerable code introduced in 2.9.0)
https://github.com/ruby/json/security/advisories/GHSA-x2f5-4prf-w687
Fixed by: https://github.com/ruby/json/commit/fd6a65bd08e5f3a429c03919ebfd8dd19158f095 (v2.19.9)