CVE-2026-17573 Double Free in H5D__chunk_copy() in HDF5 via a Crafted Chunk-Index Size Field
A double free vulnerability in the HDF5 library allows attackers to cause a denial of service via a crafted file processed by h5repack.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-17573?
CVE-2026-17573 is a medium-severity use after free vulnerability in Hdfgroup Hdf5, published on 27 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
A double free vulnerability was discovered in the HDF5 library. Processing a crafted HDF5 file containing an oversized chunk size field via h5repack may cause the application to abort due to a double free.
Weakness: CWE-415
Which versions are affected by CVE-2026-17573?
It affects 1 product.
Products include Hdfgroup Hdf5.
How do I fix CVE-2026-17573?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-17573 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-17573 exists.
Other vulnerabilities in Hdfgroup Hdf5
Sources
Also known as AZL-94013, DEBIAN-CVE-2026-17573, ECHO-9710-769a-b90b, GHSA-3536-73hp-9xm7, JLSEC-2026-1385, UBUNTU-CVE-2026-17573.