CVE-2026-26200Public exploit

Application crash via oversized compound datatype conversion

Published Feb 19, 2026 · Updated Feb 19, 2026

Heap buffer overflow in HDF5 before 1.14.4-2 allows attackers to crash applications by parsing a crafted HDF5 file. During nested compound datatype conversion, H5T__conv_struct_opt calls memmove with a size derived from a crafted string datatype, exceeding the allocated heap buffer. Exploitation requires a target user or server-side process to parse attacker-controlled HDF5 data; a crash is demonstrated, while code execution is unverified.

CVSS severity7.8
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in HDF5 before 1.14.4-2 allows attackers to crash applications by parsing a crafted HDF5 file. During nested compound datatype conversion, H5T__conv_struct_opt calls memmove with a size derived from a crafted string datatype, exceeding the allocated heap buffer. Exploitation requires a target user or server-side process to parse attacker-controlled HDF5 data; a crash is demonstrated, while code execution is unverified.

The record

CVE
CVE-2026-26200
Published
Feb 19, 2026
Updated
Feb 19, 2026
Vendor
The HDF Group
Product
HDF5
Classifications
CWE-131, CWE-122, CWE-787, CAPEC-92, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 19, 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.

  1. Affected versionversion=< 1.14.4-2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The HDF Group · HDF5version=< 1.14.4-2

Published CVSS scores

7.8GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8Red HatCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-131Incorrect Calculation of Buffer Size
CWE-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write
CAPEC-92Forced Integer Overflow
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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