CVE-2026-19027

MEDIUM CVSS 4.0: 6.9 EPSS 0.19%
Updated Oct 07, 2026
The Hdf Group
Parameter Value
CVSS 6.9 (MEDIUM)
Affected Versions before 2.3.0
Type CWE-125 (Out-of-bounds Read)
Vendor The Hdf Group
Public PoC No

The H5Z__nbit_decompress_one_byte, H5Z__nbit_decompress_one_nooptype, and H5Z__nbit_decompress_one_atomic functions in H5Znbit.c in HDF5 prior to 2.3.0 advance a read index into the compressed chunk buffer without bounding it against the buffer's actual size. This allows attackers to cause an out-of-bounds heap read, and in constrained cases disclosure of adjacent heap memory into decompressed dataset values, via a crafted HDF5 file whose N-Bit filter parameters describe more decompressed data than the stored compressed chunk actually contains, triggered via H5Dread, e.g. by the h5ls or h5repack tools.

Attack Parameters

Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction

Impact Assessment

Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products

the hdf group:hdf5