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 through a malicious link. Microsoft has not disclosed which Telephony Service routine mismanages attacker-controlled input or how the write crosses its heap allocation boundary. Exploitation requires a user to select the link, after which code executes in the affected service context.
Summary
What happened
A heap-based buffer overflow in Microsoft Windows Telephony Service allows remote attackers to execute code through a malicious link. Microsoft has not disclosed which Telephony Service routine mismanages attacker-controlled input or how the write crosses its heap allocation boundary. Exploitation requires a user to select the link, after which code executes in the affected service context.
The record
- CVE
- CVE-2025-21273
- Published
- Jan 14, 2025
- Updated
- Jun 9, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- CWE-122, T1203, T1204.001
- 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.
Weakness, pattern, technique
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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