NULL pointer dereference in Hdfgroup Hdf5
CVE-2026-120758
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Hdfgroup Hdf5
- The Hdf Group Hdf5 — versions < 2.3.0
Weakness classification (CWE)
References
- 0253b833-3e77-4dfe-9d57-17db1a2f0a74 (Patch, Issue Tracking)
Frequently asked questions
- What is CVE-2026-120758?
- CVE-2026-120758 is a medium-severity vulnerability in Hdfgroup Hdf5, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2026-11-03.
- How severe is CVE-2026-120758?
- Medium severity. CVSS v3 base score is 5.5 out of 10.