{"id":"CVE-2026-120758","title":"NULL Pointer Dereference in H5HL_unprotect via Corrupted File","summary":"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_unpro…","severity":"medium","cvss":5.4,"cvssVector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P","cvssSource":"cna","cwe":["CWE-476"],"vendor":"The HDF Group","product":"HDF5","affected":["HDF5 < 2.3.0"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-03T17:51:46.159121Z"},"published":"2026-11-03","updated":"2026-11-03","sourceUpdated":"2026-11-03T17:52:03.376Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-120758","references":[{"url":"https://github.com/HDFGroup/hdf5/pull/6377"}],"tags":["cve.org"],"epss":0.0014,"epssPercentile":0.03367,"ingestedAt":"2026-11-05T20:33:06.330Z","slug":"CVE-2026-120758","body":"## Overview\n\nHDF5 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.\n\n## Affected\n\n- `HDF5 < 2.3.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}