Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HSummary
CVE-2026-34734 is a high-severity Use After Free (CWE-416) vulnerability in Hdfgroup Hdf5. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34734 is a heap-use-after-free vulnerability (CWE-416) affecting the h5dump helper utility in HDF5 versions 1.14.1-2 and earlier. HDF5 is software for managing data, and the flaw arises when processing a malicious .h5 file. Specifically, an object allocated by H5D__typeinfo_init_phase3 and freed by H5D__typeinfo_term is improperly referenced in a memmove call from H5T__conv_struct, leading to the use-after-free condition. The vulnerability was published on 2026-04-09 and carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).
Exploitation requires local access with low attack complexity and no privileges, but relies on user interaction, such as convincing a user to run h5dump on a supplied malicious .h5 file. A successful attacker can achieve high impacts on confidentiality, integrity, and availability, potentially enabling arbitrary code execution or system compromise on the affected machine.
The primary reference is the security advisory published by the HDF Group at https://github.com/HDFGroup/hdf5/security/advisories/GHSA-w7v2-9cmr-pwwj, which security practitioners should review for details on available patches and recommended mitigations.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21020
Vulnerability Data
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…
more
memmove call from H5T__conv_struct. The original object was allocated by H5D__typeinfo_init_phase3 and freed by H5D__typeinfo_term.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 3 hardening rules · 3 OS baselines
V1.4.3
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover use-after-free bugs through dynamic analysis or fuzzing.
Engineering principles can require memory-safe constructs or languages that structurally avoid introducing use-after-free.
Process isolation confines the blast radius of use-after-free memory corruption to a single execution domain.
Memory protection controls limit exploitation impact by blocking unauthorized code execution from dangling pointers.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly incorporate memory-safety tooling and reviews that prevent most use-after-free defects.
Lifecycle management includes secure development and maintenance phases that reduce memory-safety defects.
Vulnerability identification processes can discover use-after-free issues via scanning or analysis but do not prevent their introduction.
Routine patching removes known use-after-free instances after they have been introduced in released software.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect use-after-free bugs before release.
Secure SDLC mandates memory-safety practices that reduce use-after-free defects.
Application security requirements can specify memory-management rules that mitigate use-after-free.
Secure architecture principles include memory-safety design choices that limit use-after-free exposure.
Secure coding standards directly prescribe avoidance of use-after-free patterns.
Change-management processes help ensure memory-safety fixes are deployed consistently.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248592 OL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 8 (1 rule)
- V-230279 RHEL 8 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416
RHEL 9 (1 rule)
- V-257794 RHEL 9 must clear memory when it is freed to prevent use-after-free attacks. prevents CWE-416