CVE-2026-57432

Name	CVE-2026-57432
Description	Perl versions through 5.43.10 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack. S_measure_struct adds each item's size times its repeat count to a running total with no overflow check, so a large repeat count in a pack or unpack template wraps the signed SSize_t total negative. The @, X, and x position codes then guard their moves with a signed length comparison that passes when the length is negative, advancing the buffer pointer out of bounds. A template derived from untrusted input can read heap memory past the buffer and return it to the caller.
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	1138905, 1142036

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
perl (PTS)	bullseye	5.32.1-4+deb11u3	vulnerable
	bullseye (security)	5.32.1-4+deb11u5	vulnerable
	bookworm	5.36.0-7+deb12u3	vulnerable
	bookworm (security)	5.36.0-7+deb12u2	vulnerable
	trixie	5.40.1-6	vulnerable
	forky, sid	5.42.2-3	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
perl	source	(unstable)	5.40.1-8			1138905, 1142036

Notes

https://lists.security.metacpan.org/cve-announce/msg/41780102/
Fixed by: https://github.com/Perl/perl5/commit/5f7eb6bbbe0510964e3fb1d6bb691e5445913e55 (v5.43.11)
Fixed by: https://github.com/Perl/perl5/commit/40754edc72dd3e513d758153c0e2f0215897740e (v5.43.11)