CVE-2026-120758

Name	CVE-2026-120758
Description	HDF5 through 2.2.0 contains a NULL pointer dereference vulnerability in H5HL_unprotect() in src/H5HL.c. H5HL_protect() pins a single metadata cache entry for a local heap, either the heap prefix or the separate data block, and H5HL_unprotect() unpins it on the final unprotect. When the metadata cache destroys a corrupted local heap entry, H5HL__prfx_dest() unlinks it from the heap by setting heap->prfx or heap->dblk to NULL. A crafted HDF5 file can therefore reach H5HL_unprotect() with no cached object to unpin, and the function passes the NULL pointer to H5AC_unpin_entry(). This causes an assertion failure in debug builds and a NULL pointer dereference and crash in release builds. An attacker who can get a user or application to open and traverse a malicious file can cause a denial of service.
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)	bookworm	1.10.8+repack1-1	vulnerable
	trixie	1.14.5+repack-3	vulnerable
	forky	2.2.0+repack-5	vulnerable
	sid	2.2.0+repack-6	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

Notes

https://github.com/HDFGroup/hdf5/issues/6403
https://github.com/HDFGroup/hdf5/pull/6377
https://github.com/HDFGroup/hdf5/commit/91fc37c3325264e67699408e3a190fe4f329bf85
HDF not covered by security support, see https://bugs.debian.org/1117722