Out-of-bounds Read in Hdfgroup Hdf5
CVE-2026-120755
HDF5 through 2.2.0 contains an out-of-bounds read vulnerability in H5Z__filter_szip() in src/H5Zszip.c. When decoding a szip-compressed chunk, the function subtracts the 4-byte uncompressed-length header from the chunk length without first verifying that the chunk is at least 4 bytes long. A truncated or corrupted chunk shorter than the header causes the length calculation to wrap around to a very large value, and the decompressor reads far past the end of the chunk buffer. An attacker who can get a user or application to read a dataset from a crafted HDF5 file can cause a denial of service. Only builds with szip support (libaec or the szip library) are affected.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Hdfgroup Hdf5
- The Hdf Group Szip Filter — versions < 2.3.0
Weakness classification (CWE)
References
- 0253b833-3e77-4dfe-9d57-17db1a2f0a74 (Patch, Issue Tracking)
Frequently asked questions
- What is CVE-2026-120755?
- CVE-2026-120755 is a medium-severity vulnerability in Hdfgroup Hdf5, classified under Out-of-bounds Read. CVSS score: 5.5/10. Published 2026-11-03.
- How severe is CVE-2026-120755?
- Medium severity. CVSS v3 base score is 5.5 out of 10.