Remote code execution via Kerberos response overflow
Published Nov 12, 2024 · Updated Jul 8, 2025
Numeric truncation in Microsoft Windows Server KDC Proxy allows remote attackers to execute code via a crafted Kerberos response. KpsPackProxyResponse passes an attacker-controlled response length into MSASN.1 encoding, where 32-bit size arithmetic wraps and memcpy writes beyond the heap buffer. KPSSVC must be running on a domain-joined server, and exploitation requires a controlled Kerberos endpoint to return the declared multi-gigabyte response.
Summary
What happened
Numeric truncation in Microsoft Windows Server KDC Proxy allows remote attackers to execute code via a crafted Kerberos response. KpsPackProxyResponse passes an attacker-controlled response length into MSASN.1 encoding, where 32-bit size arithmetic wraps and memcpy writes beyond the heap buffer. KPSSVC must be running on a domain-joined server, and exploitation requires a controlled Kerberos endpoint to return the declared multi-gigabyte response.
The record
- CVE
- CVE-2024-43639
- Published
- Nov 12, 2024
- Updated
- Jul 8, 2025
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-197, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 12, 2024CVE publishedPublication date reported by the CVE source.
- Jul 8, 2025Record 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 <10.0.17763.6532
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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