Bug 2565367 (CVE-2026-120689)

Summary: CVE-2026-120689 hdf5: hdf5: Denial of Service via uncontrolled recursion in B-tree processing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: bbrownin, eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in HDF5. When traversing internal B-tree data structures, the library fails to properly validate child node relationships if a node is already loaded in the metadata cache. An attacker could exploit this vulnerability by enticing a user or application to open a specially crafted HDF5 file containing self-referencing tree nodes. This triggers unbounded recursion and stack exhaustion, causing the application to crash and resulting in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2565826, 2565828    
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Description OSIDB Bzimport 2026-11-02 19:52:45 UTC 
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 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.