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TI-2026-15552 Aliases CVE-2026-19028GHSA-2hg9-348w-39gj

HDF5 integer underflow in Fletcher32 filter leads to massive out-of-bounds read

Priority MEDIUM 63CWE-125Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · 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. Impact type from CWE-125 and the CVSS impact.

Summary

H5Z__filter_fletcher32 in H5Zfletcher32.c in HDF5 prior to 2.3.0 computes the data length to checksum by subtracting the 4-byte trailing checksum size from the input buffer size without checking that the buffer is at least 4 bytes, allowing a size_t underflow. This allows attackers to cause a denial of service (massively out-of-bounds read and application crash in H5_checksum_fletcher32) via a crafted HDF5 file with a Fletcher32-filtered chunk smaller than 4 bytes, triggered via H5Dread, e.g. by the h5ls or h5dump tools.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00195 9th percentileScored 2026-11-07
Fix Partial Red Hat: 1 advisoryRed Hat: 1 fixed, 1 without a fix

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

VendorProductAffected versionsFixed inStatusSource
The HDF GroupHDF5up to 2.3.0—No fix listedCNA
  • 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.

CPEVersionsRoleVendor
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 Important
    Red 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 →

ProductStatusPlan or fix
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet
Red Hat Hardened ImagesFixed RHSA-2026:73539

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-19028
  2. 2026-10-03 Alias added: GHSA-2hg9-348w-39gj

References

Other 3

  • 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
See all 150 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences