Vulnerability · Published Apr 9, 2026 · Assigned by GitHub_M
CVE-2026-34734HDF5: H5T__conv_struct Use After Free
High 7.8
In plain English
A high-severity use-after-free in hdf5 from HDFGroup. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities).
Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 90.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | hdf5 | no fix listed | DEBIAN-CVE-2026-34734 |
| Debian:13 | hdf5 | no fix listed | DEBIAN-CVE-2026-34734 |
| Debian:14 | hdf5 | no fix listed | DEBIAN-CVE-2026-34734 |
| Ubuntu:22.04:LTS | hdf5 | no fix listed | UBUNTU-CVE-2026-34734 |
| Ubuntu:24.04:LTS | hdf5 | no fix listed | UBUNTU-CVE-2026-34734 |
| Ubuntu:25.10 | hdf5 | no fix listed | UBUNTU-CVE-2026-34734 |
| Ubuntu:26.04:LTS | hdf5 | no fix listed | UBUNTU-CVE-2026-34734 |
| Ubuntu:26.10 | hdf5 | no fix listed | UBUNTU-CVE-2026-34734 |
Affected products (as reported)
Weakness: CWE-416, CWE-825 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- https://github.com/HDFGroup/hdf5/security/advisories/GHSA-w7v2-9cmr-pwwj x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2026-34734 vdb-entry, x_refsource_REDHAT
- RHBZ#2457034 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34734.json x_sadp-csaf-vex