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TI-2026-26978 Aliases CVE-2026-34734

HDF5: H5T__conv_struct Use After Free

Priority HIGH 69CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 1 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

HDF5 is software for managing data. In 1.14.1-2 and earlier, a heap-use-after-free was found in the h5dump helper utility. An attacker who can supply a malicious h5 file can trigger a heap use-after-free. The freed object is referenced in a memmove call from H5T__conv_struct. The original object was allocated by H5D__typeinfo_init_phase3 and freed by H5D__typeinfo_term.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.002 9th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
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
Total

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 1.14.1-2—No fix listedCNA
  • hdf5 VendorThe HDF Group Affected up to 1.14.1-2 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:hdfgroup:hdf5:*:*:*:*:*:*:*:*before 1.14.1-2VulnerableThe HDF Group
  • cpe:2.3:a:hdfgroup:hdf5:*:*:*:*:*:*:*:* Versions before 1.14.1-2 Vulnerable ·The HDF Group

Remediation

Red Hat 1 advisory

  • RHSA-2026:61630 Released 2026-08-31 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images hdf5-2.2.0-0.1.1.hum1@aarch64, hdf5-2.2.0-0.1.1.hum1@src, hdf5-2.2.0-0.1.1.hum1@x86_64 +18

Vendor assessments

Red Hat

Red Hat rating: Important. 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-2026:61630

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-34734

References

Exploit 1

  • 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-2022-09532 Heap-based buffer overflow in HDF Group libhdf5 CVSS 3.1HIGH 7.8
  • TI-2022-09492 Out-of-bounds write in HDF Group libhdf5 CVSS 3.1HIGH 7.8
See all 140 →

Sources

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