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CVE-2026-58599 Microsoft CVE debrief

Microsoft has released a patch for a heap-based buffer overflow vulnerability in the HEVC Video Extensions, which could allow an unauthorized attacker to execute code locally. The vulnerability has a CVSS score of 7.8 and is considered high severity. Affected products include HEVC Video Extensions, HEVC Video Extensions for Licensed Applications, and HEVC Video Extensions from Device Manufacturer, across various Windows versions.

Vendor
Microsoft
Product
HEVC Video Extensions
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-10-08
Advisory published
2026-09-08
Advisory updated
2026-10-08

Who should care

IT and security teams responsible for systems and applications using HEVC Video Extensions should prioritize patching this vulnerability. This includes teams managing Windows versions affected by the vulnerability, as well as developers and administrators working with HEVC Video Extensions.

Why it matters

The heap-based buffer overflow vulnerability in HEVC Video Extensions requires immediate attention from defenders due to its potential for local code execution by unauthorized attackers. IT and security teams must prioritize patching affected systems and applications, and verify patch deployment to mitigate this high-severity vulnerability.

  • Potential for local code execution by unauthorized attackers
  • Requires immediate patching attention from IT and security teams
  • Affected systems and applications need to be inventoried and assessed for exposure

Technical summary

The vulnerability is a heap-based buffer overflow in the Microsoft Windows Codecs Library, specifically in the HEVC Video Extensions. This allows an unauthorized attacker to execute code locally. The vulnerability has a CVSS score of 7.8 and is considered high severity.

Defensive priority

Defenders should prioritize patching this vulnerability, especially for systems and applications that use HEVC Video Extensions. This requires immediate attention from IT and security teams to ensure the patch is applied to all affected systems.

Recommended defensive actions

  • Apply the patch from Microsoft for the affected HEVC Video Extensions
  • Inventory and assess exposure of systems and applications using HEVC Video Extensions
  • Verify patch deployment on affected systems

Evidence notes

The CVE record and NVD vulnerability detail provide information on the vulnerability, its severity, and affected products. Microsoft's advisory is referenced, indicating a patch is available.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-58599 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-58599

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-58599 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-58599

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • HEVC Video Extensions Remote Code Execution Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/58xxx/CVE-2026-58599.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58599

    Supplemental source - vendor-advisory, patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.