Code execution via undisclosed heap-based buffer overflow
Published Jan 13, 2026 · Updated Jan 13, 2026
Heap-based buffer overflow in Windows Media on affected Windows releases allows local users to execute code through crafted media. Microsoft identifies the memory-corruption class but has not published the affected parser, media format, or incorrect bounds operation that overruns a heap buffer. Exploitation requires user interaction with attacker-controlled content and can run code in the victim's security context.
Summary
What happened
Heap-based buffer overflow in Windows Media on affected Windows releases allows local users to execute code through crafted media. Microsoft identifies the memory-corruption class but has not published the affected parser, media format, or incorrect bounds operation that overruns a heap buffer. Exploitation requires user interaction with attacker-controlled content and can run code in the victim's security context.
The record
- CVE
- CVE-2026-20837
- Published
- Jan 13, 2026
- Updated
- Jan 13, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-122, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 13, 2026CVE publishedPublication date reported by the CVE source.
- Jan 13, 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=10.0.17763.0 <10.0.17763.8276
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.
Public exploit references
No public exploit references are available in this record.
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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