HDF Group HDF5 up to 2.3.0 N-Bit Filter H5Znbit.c out-of-bounds

Summaryinfo

A vulnerability marked as critical has been reported in HDF Group HDF5 up to 2.3.0. This impacts the function H5Z__nbit_decompress_one_byte/H5Z__nbit_decompress_one_nooptype/H5Z__nbit_decompress_one_atomic of the file H5Znbit.c of the component N-Bit Filter. Performing a manipulation results in out-of-bounds. This vulnerability is cataloged as CVE-2026-19027. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in HDF Group HDF5 up to 2.3.0. It has been classified as critical. This affects the function H5Z__nbit_decompress_one_byte/H5Z__nbit_decompress_one_nooptype/H5Z__nbit_decompress_one_atomic of the file H5Znbit.c of the component N-Bit Filter. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The 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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-19027 since 08/06/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/06/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at CNNVD (CNNVD-2026-52356562) and EUVD (EUVD-2026-53678). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Database Software

Vendor

• HDF Group

Name

• HDF5

Version

• 2.0
• 2.1
• 2.2
• 2.3.0

License

• free

CPE 2.3info

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CPE 2.2info

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Be aware that VulDB is the high quality source for vulnerability data.

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