Memory corruption via zero-size group-name request
Published Jul 20, 2026 · Updated Jul 20, 2026
Buffer underflow in HDF5 1.14.6 and earlier allows context-dependent attackers to corrupt memory via a zero-size group-name request. H5G_get_name copies a cached group path and, when size is zero, writes a null terminator to name[size - 1], addressing one byte before the supplied buffer. Reachability requires a consuming application to pass a non-null buffer and attacker-influenced zero size to H5Iget_name; the demonstrated consequence is a one-byte underwrite, with no reported code execution.
Summary
What happened
Buffer underflow in HDF5 1.14.6 and earlier allows context-dependent attackers to corrupt memory via a zero-size group-name request. H5G_get_name copies a cached group path and, when size is zero, writes a null terminator to name[size - 1], addressing one byte before the supplied buffer. Reachability requires a consuming application to pass a non-null buffer and attacker-influenced zero size to H5Iget_name; the demonstrated consequence is a one-byte underwrite, with no reported code execution.
The record
- CVE
- CVE-2026-26199
- Published
- Jul 20, 2026
- Updated
- Jul 20, 2026
- Vendor
- The HDF Group
- Product
- HDF5
- Classifications
- CWE-124
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 20, 2026CVE publishedPublication date reported by the CVE source.
- Jul 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<= 1.14.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- H5Iget_name zero-size AddressSanitizer proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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