Is CVE-2026-34734 in the CISA KEV catalog?

No. CVE-2026-34734 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34734?

CVE-2026-34734 has a CVSS v3 base score of 7.8 (HIGH).

What is the EPSS score for CVE-2026-34734?

CVE-2026-34734 has an EPSS score of 0.19% (9th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34734?

Upgrade hdf5 to 1.14.1-2 or later.

CVE & CISA-KEV Catalog

CVE-2026-34734

HIGH

7.8

CVSS v3

NVD

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.

CWE-416Use After Free CWE-825

How to fix

Remediation Available

hdf5NVD

Affected:< 1.14.1-2Fixed in:1.14.1-2CVE-2026-34734derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploit Intelligence

0.19%probability of exploitation in 30 days

9thpercentile

Low risk: more likely to be exploited than 9% of all known CVEs.

References

Exploit1

github.com

Other references3

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-30.