CVE-2026-26199

HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If `H5Iget_name` is invoked on a group id with `0` for the size parameter, it will underflow when trying to place a null terminator in the buffer. This can occur if `H5Iget_name` is invoked in a way where `size` can be forced to zero, and there is important data before the `name` buffer.

CVSS 4.0

5.9CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

EPSS

0.4% chance of exploitation in the next 30 days; higher than 28% of CVEs (scores of 2026-10-25)

CWE

CWE-124

Published

2026-07-20

Modified

2026-10-24

Record from

the NVD, synced 2026-10-25

Affected

• hdfgroup:hdf5

References

• https://github.com/HDFGroup/hdf5/blob/develop/src/H5Gname.c#L474
• https://github.com/HDFGroup/hdf5/security/advisories/GHSA-5c6x-jmgf-f5vc
• https://github.com/HDFGroup/hdf5/security/advisories/GHSA-5c6x-jmgf-f5vc

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