Remote code execution via heap buffer overflow
Published Jan 14, 2025 · Updated Jun 9, 2026
A heap-based buffer overflow in Microsoft Windows Telephony Service allows remote attackers to execute code after user interaction. Microsoft identifies heap corruption but has not published the Telephony Service routine, malformed field, or incorrect memory operation that triggers the overflow. Exploitation requires a user on an affected Windows system to process attacker-controlled input, after which code can run in the service context.
Summary
What happened
A heap-based buffer overflow in Microsoft Windows Telephony Service allows remote attackers to execute code after user interaction. Microsoft identifies heap corruption but has not published the Telephony Service routine, malformed field, or incorrect memory operation that triggers the overflow. Exploitation requires a user on an affected Windows system to process attacker-controlled input, after which code can run in the service context.
The record
- CVE
- CVE-2025-21306
- Published
- Jan 14, 2025
- Updated
- Jun 9, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- CWE-122, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 14, 2025CVE publishedPublication date reported by the CVE source.
- Jun 9, 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=10.0.10240.0 <10.0.10240.20890
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.
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Technologies
Your stack
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Your stack
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