High severity · published Apr 9, 2026
CVE-2026-34734
HDF5: H5T__conv_struct Use After Free
7.8
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 9% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HD
hdf5 · HDFGroup
<= 1.14.1-2 · source: vendor, NVD
RH
Red Hat Enterprise Linux AI (RHEL AI) 3 · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34734
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34734
Exploit
https://github.com/HDFGroup/hdf5/security/advisories/GHSA-w7v2-9cmr-pwwj
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-34734
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2457034
security.access.redhat.com
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34734.json
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