Quick answers
- Is CVE-2026-120689 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-120689 being exploited in the wild.
- How severe is CVE-2026-120689?
- Informational severity, published 2 November 2026.
- Which products and versions are affected?
- Hdfgroup Hdf5 through 2.2.0.
- Is there a fix for CVE-2026-120689?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-120689 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-120689?
- Check whether you run Hdfgroup Hdf5 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The H5B__iterate_helper() function in src/H5B.c fails to validate that a child node's level matches the expected level when iterating version 1 B-trees. A crafted file with a B-tree child pointer that refers back to an already-cached node (including self-referential pointers) bypasses the level check performed during cache deserialization, causing unbounded recursion and stack exhaustion. The vulnerability is triggered when applications call H5Gget_info() or H5Gget_num_objs() on a group.
Affected products
- HDFGroup HDF5 through 2.2.0
Timeline
- 2026-05-12: disclosed
- 2026-10-08: other: Fixed in PR #6685
- 2026-11-02: advisory