CVE-2026-19025

Name	CVE-2026-19025
Description	H5O__layout_decode in H5Olayout.c in HDF5 through 2.3.0 does not validate that a chunked dataset's stored chunk-layout dimensionality matches its dataspace rank when an existing dataset is opened, whereas this check is performed only at dataset-creation time. This allows attackers to cause a denial of service (divide-by-zero and application crash in H5S__hyper_iter_get_seq_list in src/H5Shyper.c) via a crafted HDF5 file with mismatched chunk/dataspace ranks that is opened and read via H5Dopen2 and H5Dread, e.g. by the h5repack tool.
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
hdf5 (PTS)	bullseye	1.10.6+repack-4+deb11u1	vulnerable
	bookworm	1.10.8+repack1-1	vulnerable
	trixie	1.14.5+repack-3	vulnerable
	forky	1.14.6+repack-2	vulnerable
	sid	2.1.0+repack-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
hdf5	source	(unstable)	(unfixed)	unimportant

https://github.com/HDFGroup/hdf5/issues/6491
HDF not covered by security support, see https://bugs.debian.org/1117722