LiveActive security incident?Get immediate response
CVE Record

CVE-2021-36977: matio (aka MAT File I/O Library) 1.5.20 and 1.5.21 has a heap-based buffer overflow in H5MM_memcpy (called...

matio (aka MAT File I/O Library) 1.5.20 and 1.5.21 has a heap-based buffer overflow in H5MM_memcpy (called from H5MM_malloc and H5C_load_entry), related to use of HDF5 1.12.0.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a memory corruption flaw in matio, a library for reading and writing MATLAB MAT files. The supplied record names matio 1.5.20 and 1.5.21, related to HDF5 1.12.0. Business risk depends on whether affected software processes untrusted MAT/HDF5 files.

Executive priority

Treat this as an inventory and containment priority, not an emergency solely from the supplied evidence. Escalate if affected components process external files in production, customer-facing, or automated analysis environments.

Technical view

CVE-2021-36977 describes a heap-based buffer overflow in H5MM_memcpy, reached through H5MM_malloc and H5C_load_entry, in matio 1.5.20 and 1.5.21 when used with HDF5 1.12.0. The bundle provides no CVSS, CWE, fixed version, or confirmed exploitation details.

Likely exposure

Exposure is most likely in applications, research pipelines, data import services, or analysis tools using matio 1.5.20 or 1.5.21 with HDF5 1.12.0, especially where external MAT/HDF5 files are accepted.

Exploitation context

The source bundle does not show CISA KEV listing or any cited confirmation of active exploitation. The risk is tied to malformed file parsing, but the provided sources do not establish real-world exploit use or impact beyond heap overflow behavior.

Researcher notes

Evidence is limited to CVE, OSV, oss-fuzz, and HDF5 issue references. The bundle supports the affected matio versions, HDF5 1.12.0 relationship, and heap overflow location, but not exploitability, CVSS severity, or a named patch.

Mitigation direction

  • Inventory matio and HDF5 versions in applications and build artifacts.
  • Check matio, HDF5, OSV, and vendor guidance for fixed versions or recommended workarounds.
  • Avoid processing untrusted MAT/HDF5 files with affected library combinations.
  • Sandbox or isolate workflows that must parse external MAT/HDF5 files.
  • Prioritize upgrades where parsing happens in automated or user-facing services.

Validation and detection

  • Confirm whether matio 1.5.20 or 1.5.21 is present.
  • Confirm whether HDF5 1.12.0 is linked or bundled.
  • Map all workflows that accept external MAT or HDF5 files.
  • Verify untrusted file parsing is blocked, sandboxed, or routed to updated components.
  • Review crash telemetry for unexplained parser failures in affected workflows.
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.

cve · low confidence lookup

CVE-2021-36977 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
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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