HDF5 out-of-bounds heap read in N-Bit filter decompression

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-19027
StatePUBLISHED
AssignerHDFG
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-06 00:16:53 UTC
Updated2026-08-06 15:16:46 UTC
DescriptionThe H5Z__nbit_decompress_one_byte, H5Z__nbit_decompress_one_nooptype, and H5Z__nbit_decompress_one_atomic functions in H5Znbit.c in HDF5 through 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.

Risk And Classification

Primary CVSS: v4.0 6.9 MEDIUM from 0253b833-3e77-4dfe-9d57-17db1a2f0a74

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.001270000 probability, percentile 0.027180000 (date 2026-08-09)

Problem Types: CWE-125 | CWE-125 CWE-125 Out-of-bounds read

VersionSourceTypeScoreSeverityVector
4.00253b833-3e77-4dfe-9d57-17db1a2f0a74Secondary6.9MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS6.9MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Passive
Confidentiality
Low
Integrity
None
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA The HDF Group HDF5 affected <=2.3.0 Not specified

References

ReferenceSourceLinkTags
github.com/HDFGroup/hdf5/pull/6497 0253b833-3e77-4dfe-9d57-17db1a2f0a74 github.com
github.com/HDFGroup/hdf5/issues/6489 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/HDFGroup/hdf5/issues/6492 0253b833-3e77-4dfe-9d57-17db1a2f0a74 github.com
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