CVE-2026-57077

Name	CVE-2026-57077
Description	YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len. In the bundled libsyck newline_len and is_newline dereference the scan pointer, and the following byte for a "\r\n" pair, with no NUL-terminator or bounds check. During block-scalar lexing at a document boundary the scan runs one byte past the heap lexer buffer. This is an incomplete fix of CVE-2025-11683, on a lexer path the earlier fix did not cover. Any caller that runs Load or LoadFile on an untrusted document with a block scalar at a document boundary reaches the over-read.
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)
Debian Bugs	1142267

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libyaml-syck-perl (PTS)	bullseye	1.34-1	vulnerable
	bullseye (security)	1.34-1+deb11u1	vulnerable
	bookworm, bookworm (security)	1.34-2+deb12u2	vulnerable
	trixie (security), trixie	1.34-2+deb13u2	vulnerable
	forky	1.36-3	vulnerable
	sid	1.47-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libyaml-syck-perl	source	(unstable)	(unfixed)			1142267

Notes

https://www.openwall.com/lists/oss-security/2026/07/17/4
Fixed by: https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b (1.47)