HDF5 out-of-bounds heap read in N-Bit filter decompression
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · High
- Fix status
- Partial Red Hat: 1 fixed, 1 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| The HDF Group | HDF5 | up to 2.3.0 | — | No fix listed | CNA |
- HDF5 VendorThe HDF Group Affected up to 2.3.0 Fixed in — No fix listed CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:hdfgroup:hdf5:*:*:*:*:*:*:*:* | — | — | The HDF Group |
- cpe:2.3:a:hdfgroup:hdf5:*:*:*:*:*:*:*:* Versions — — ·The HDF Group
Remediation
Red Hat 1 advisory
- RHSA-2026:73539 Released 2026-09-29 · Red Hat rating ImportantRed Hat Hardened Images RPMs Security Update
- Red Hat Hardened Images hdf5-2.2.0-0.1.2.hum1@aarch64, hdf5-2.2.0-0.1.2.hum1@src, hdf5-2.2.0-0.1.2.hum1@x86_64 +18
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet |
| Red Hat Hardened Images | Fixed | RHSA-2026:73539 |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-19027
- 2026-10-03 Alias added: GHSA-2pvh-qgr3-wp2r
References
More The HDF Group vulnerabilities
- TI-2025-28698 hdf5 v1.14.6 was discovered to contain a heap buffer overflow via the H5Z__filter_scaleoffset function. CVSS 3.1HIGH 8.8
- TI-2025-28697 hdf5 v1.14.6 was discovered to contain a heap buffer overflow via the H5VM_memcpyvv function. CVSS 3.1HIGH 8.8
- TI-2020-13412 Buffer Overflow vulnerability in function H5S_close in H5S.c in HDF5 1.10.4 allows remote… CVSS 3.1HIGH 8.8
- TI-2021-15413 Buffer Overflow vulnerability in HDFGroup hdf5-h5dump 1.12.0 through 1.13.0 allows… CVSS 3.1HIGH 7.5
- TI-2026-26978 HDF5: H5T__conv_struct Use After Free CVSS 3.1HIGH 7.8
- TI-2026-15548 HDF5 H5Pget_fill_value NULL Pointer Dereference via Malformed Fill Value Message CVSS 4.0HIGH 8.2
Sources
- CVE-2026-19027 · CVE Program
- CVE-2026-19027 · NVD
- FIRST EPSS
- GHSA-2pvh-qgr3-wp2r · GitHub Advisory Database · CC BY 4.0
- CVE-2026-19027 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences