Quick answers
- Is CVE-2026-17574 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-17574 being exploited in the wild.
- How severe is CVE-2026-17574?
- Informational severity, with a CVSS score of 5.2, published 27 July 2026.
- Which products and versions are affected?
- The HDF Group HDF5 <= 2.1.1.
- Is there a fix for CVE-2026-17574?
- 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-2026-17574 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-17574?
- Check whether anything you run is named in the advisory. 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
A NULL pointer dereference and reachable assertion vulnerability exists in HDF5's H5O__dtype_decode_helper() and H5T_set_loc() functions. The root cause is a failure to validate the 'vlen.type' field during the decoding of variable-length datatypes; if the field contains a value other than H5T_VLEN_SEQUENCE or H5T_VLEN_STRING, it triggers an assertion failure in debug builds or a segmentation fault in release builds. An attacker can exploit this by providing a malformed HDF5 file to an application that reads its attributes. A fix has been developed that adds validation checks during decoding and ensures file pointers are not NULL before processing.
Affected products
- The HDF Group HDF5 <= 2.1.1
Timeline
- 2026-07-27: disclosed
- 2026-07-27: advisory