RCE in H5io
CVE-2026-120499
h5io before 0.2.6 contains a code injection vulnerability in read_hdf5() that allows attackers to execute arbitrary code by supplying a crafted HDF5 file. Attackers can store Python code in a node titled timezone, which _triage_read() passes to eval() with builtins reachable, name an arbitrary module in class or custom-object nodes that _import_class() imports, or place pickled objects in pd_dataframe or pd_series nodes that pandas deserializes on read.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/h5io/h5io/blob/h5io-0.2.5/h5io/_h5io.py (technical-description)
- github.com/h5io/h5io/commit/afff1d61b31790f8c27e6c577bb7703eb1883ddd (patch)
- h5io h5io-0.2.6 Release Notes (release-notes)
- GitHub Security Advisory (GHSA-vwvw-f6v4-w737) (vendor-advisory)
- VulnCheck Advisory: h5io before 0.2.6 Arbitrary Code Execution via read_hdf5 (third-party-advisory)
Frequently asked questions
- What is CVE-2026-120499?
- CVE-2026-120499 is a high-severity vulnerability in H5io, classified under Eval Injection. CVSS score: 7.8/10. Published 2026-11-05.
- How severe is CVE-2026-120499?
- High severity. CVSS v3 base score is 7.8 out of 10.