{"id":"CVE-2026-120689","title":"Uncontrolled Recursion in HDF5 H5B__iterate_helper() via Crafted File","summary":"HDF5 through 2.2.0 contains an uncontrolled recursion vulnerability in H5B__iterate_helper() in src/H5B.c. When iterating a version 1 B-tree, the function does not verify that a child node’s level matches the expected level. That check i…","severity":"medium","cvss":4.3,"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:U","cvssSource":"cna","vendor":"The HDF Group","product":"HDF5","affected":["HDF5 <2.3.0"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-02T19:52:19.579381Z"},"published":"2026-11-02","updated":"2026-11-02","sourceUpdated":"2026-11-02T19:52:35.578Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-120689","references":[{"url":"https://github.com/HDFGroup/hdf5/issues/6403"}],"tags":["cve.org"],"epss":0.00176,"epssPercentile":0.07176,"ingestedAt":"2026-11-05T19:30:42.813Z","slug":"CVE-2026-120689","body":"## Overview\n\nHDF5 through 2.2.0 contains an uncontrolled recursion vulnerability in H5B__iterate_helper() in src/H5B.c. When iterating a version 1 B-tree, the function does not verify that a child node’s level matches the expected level. That check is performed only in H5B__cache_deserialize() when a node is first loaded into the metadata cache. A crafted HDF5 file whose B-tree child pointer refers back to a node already in the cache, such as a node that points to itself, bypasses the check and causes unbounded recursion, leading to stack exhaustion and a crash. This can be triggered by calling H5Gget_info() or H5Gget_num_objs() on a group in the crafted file, which reaches H5B_iterate() through H5G__obj_info() and H5G__stab_count(). An attacker who can get a user or application to open 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":24,"depthScoreParts":{"impact":23.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}