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CVE-2026-120757

7.1, high

The HDF Group HDF5 Out-of-Bounds Read Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
7.1, high high CVSS v3.1
EPSS, next 30 days
n/a
Exploitation
No public evidence
Published
3 Nov 2026yesterday

Description

HDF5 through 2.2.0 contains a heap buffer over-read vulnerability in H5L__extern_traverse() in src/H5Lexternal.c, the default traversal callback for external links. The callback locates the target file name and object path within the link’s user data using strlen() without validating the buffer against its stored size (udata_size, which was marked unused). A crafted HDF5 file containing an external link whose data is not NULL-terminated, or is too short to hold both strings, causes strlen() to read past the end of the udata heap buffer, and the derived object path pointer may also point outside the buffer. The overrun is unbounded and continues until a zero byte is found. The flaw is triggered when the malicious link is traversed, for example when opening an object through it. An attacker who can get a user or application to access a crafted file can cause a denial of service, and adjacent heap contents may be incorporated into the external file name or object path the library attempts to open.

Details

Vendor
The HDF Group
Product
HDF5
Weakness
CWE-125 (opens in a new tab)
Status
Analyzed
Updated
3 Nov 2026
Assigner
0253b833-3e77-4dfe-9d57-17db1a2f0a74

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

References 1

Patches and fixes 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Beyond this page

Is CVE-2026-120757 in your network?

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 4 Nov 2026, not the live upstream state.