Medium severity · published Jul 20, 2026
CVE-2026-26199
Buffer underflow in `H5Iget_name `/`H5G_get_name` if size is zero
6.5
CVSS
0.4%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 29% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HD
hdf5 · HDFGroup
<= 1.14.6 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-26199
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-26199
Exploit
https://github.com/HDFGroup/hdf5/blob/develop/src/H5Gname.c#L474
Vendor Advisory
https://github.com/HDFGroup/hdf5/security/advisories/GHSA-5c6x-jmgf-f5vc
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