CVE-2026-120689
Uncontrolled Recursion in HDF5 H5B__iterate_helper() via Crafted File
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.
INFO
Published Date :
Nov. 2, 2026, 8:17 p.m.
Last Modified :
Nov. 3, 2026, 4:25 p.m.
Remotely Exploit :
No
Source :
0253b833-3e77-4dfe-9d57-17db1a2f0a74
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | MEDIUM | 0253b833-3e77-4dfe-9d57-17db1a2f0a74 | ||||
| CVSS 4.0 | MEDIUM | 0253b833-3e77-4dfe-9d57-17db1a2f0a74 |
Solution
- Update HDF5 to a patched version.
- Avoid opening untrusted HDF5 files.
- Validate all input files before processing.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-120689.
| URL | Resource |
|---|---|
| https://github.com/HDFGroup/hdf5/issues/6403 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-120689 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-120689
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-120689 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-120689 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 0253b833-3e77-4dfe-9d57-17db1a2f0a74
Nov. 02, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 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 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/120xxx/CVE-2026-120689.json">CVE-2026-120689</a> Added Reference https://github.com/HDFGroup/hdf5/issues/6403 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Nov. 02, 2026
Action Type Old Value New Value Added CWE CWE-674 Added SSVC {'id': 'CVE-2026-120689', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-11-02T19:52:19.579381Z'}