CVE-2026-26197: Hdfgroup Hdf5 out-of-bounds read (CVSS 7.5)

Description

HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If a file is corrupted such that an array datatype's size, the number of elements, and the element size are not in agreement it can trigger an out of bounds read. The array datatype stores the full size of the datatype (`dt->shared->size`) separately from the number of elements (`dt->shared->u.array.nelem`) and the element size (`dt->shared->parent->shared->size`). If any one of these are corrupted so that they don't align with the others (element size * nelem = full size), it can lead to an out of bounds read. Depending on what is corrupted, it can alter the type of out of bounds read triggered. The vulnerability is present only in files that have been maliciously altered, as its generally not possible to independently alter the full size of the datatype, the element count and the element size. As such, this is only present if a malicious actor is altering files, and won't appear in regular usage.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Affected products

Hdfgroup Hdf5< 2.1.0

Remediation

Fixed in

Hdfgroup Hdf5≥ 2.1.0

Patch & vendor advisories

https://github.com/HDFGroup/hdf5/security/advisories/GHSA-gh44-7wpq-622f

References

https://github.com/HDFGroup/hdf5/security/advisories/GHSA-gh44-7wpq-622fExploitVendor Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-26197 being actively exploited?

CVE-2026-26197 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.37%.

How severe is CVE-2026-26197?

CVE-2026-26197 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.37% probability of exploitation.

Which products are affected by CVE-2026-26197?

Affected products include Hdfgroup Hdf5.

How do I fix CVE-2026-26197?

Upgrade affected software to a fixed version, for example Hdfgroup Hdf5 2.1.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-26197 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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