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 products
hdfgroup: hdf5
References5
- github.com/HDFGroup/hdf5/security/advisories/GHSA-w7v2-9cmr-pwwj ExploitVendor Advisory
- github.com/HDFGroup/hdf5/security/advisories/GHSA-w7v2-9cmr-pwwj ExploitVendor Advisory
- access.redhat.com/security/cve/CVE-2026-34734
- bugzilla.redhat.com/show_bug.cgi?id=2457034
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34734…
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 10 · as of 12 November 2026
- CWE
- CWE-416CWE-825
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.