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CVE Record

CVE-2026-26200: HDF5 Affected by H5T__conv_struct_opt Heap Buffer Overflow

HDF5 is software for managing data. Prior to version 1.14.4-2, an attacker who can control an `h5` file parsed by HDF5 can trigger a write-based heap buffer overflow condition. This can lead to a denial-of-service condition, and potentially further issues such as remote code execution depending on the practical exploitability of the heap overflow against modern operating systems. Real-world exploitability of this issue in terms of remote-code execution is currently unknown. Version 1.14.4-2 fixes the issue.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A malicious HDF5 .h5 file can cause vulnerable HDF5 versions before 1.14.4-2 to write outside heap memory. The confirmed outcome is denial of service; remote code execution is possible in theory but not proven by the provided sources.

Executive priority

Treat as high priority for environments processing external HDF5 datasets. The immediate business risk is service disruption, with uncertain but potentially serious memory-corruption impact if exploitability improves.

Technical view

CVE-2026-26200 is a write-based heap buffer overflow in HDF5's H5T__conv_struct_opt path, classified as CWE-122 and CWE-131. CVSS 3.1 is 7.8 with local attack vector, no privileges, and required user interaction. HDF5 1.14.4-2 fixes the issue.

Likely exposure

Exposure is most likely where applications, pipelines, desktops, or services parse attacker-supplied or externally sourced HDF5 .h5 files using HDF5 versions earlier than 1.14.4-2.

Exploitation context

The bundle does not show KEV listing or confirmed active exploitation. Exploitation requires getting a vulnerable parser to open or process a crafted h5 file. Denial of service is supported; practical remote-code execution remains unknown.

Researcher notes

Focus validation on dependency reachability, not just package presence. The source bundle names H5T__conv_struct_opt and a heap buffer overflow, but does not provide exploit details, proof of active exploitation, or downstream product-specific impact.

Mitigation direction

  • Upgrade HDF5 to version 1.14.4-2 or later.
  • Inventory applications that bundle or dynamically link HDF5.
  • Restrict processing of untrusted .h5 files until upgraded.
  • Check operating system vendor advisories for backported fixes.
  • Prioritize workflows that ingest external scientific or analytics datasets.

Validation and detection

  • Confirm installed HDF5 versions across hosts and containers.
  • Check application dependency manifests for hdf5 versions below 1.14.4-2.
  • Verify vendor package status against Red Hat or relevant distro advisories.
  • Review file-ingestion paths that accept user-supplied .h5 files.
  • Confirm upgraded builds link against the fixed HDF5 library.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-122: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-131: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-26200 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H1.85.9GitHub_M
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H1.85.9redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2026-26200Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPhdf5: HDF5: Denial of Service due to heap buffer overflow when parsing a crafted h5 file
other:Red Hat severity ratingcvssV3_1
  • 2026-02-19T20:05:33.115Z: Reported to Red Hat.
  • 2026-02-19T19:19:10.512Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
HDFGrouphdf5< 1.14.4-2Listed
Weakness

CWE details

CWE-122CWE-131

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-122 · source CWE mapping

Heap-based Buffer Overflow

Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-131 · source CWE mapping

Incorrect Calculation of Buffer Size

Incorrect Calculation of Buffer Size represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs