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CVE-2026-120689

MEDIUMCVSS 4.3/10EPSS 0.18%

Last modified

CVE-2026-120689 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 0.18% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 4.0
4.3/10

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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.18%

7.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
The HDF GroupHDF5<2.3.0

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-120689?
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.
How severe is CVE-2026-120689?
CVE-2026-120689 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.
How do I fix CVE-2026-120689?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST