CVE-2025-49735: Windows KDC Proxy Service (KPSSVC) Remote Code Execution Vulnerability
CVE-2025-49735 is a remote code execution vulnerability in Windows KDC Proxy Service (KPSSVC), rated Critical by Microsoft, with a CVSS 3.1 base score of 8.1 (High). An attacker can exploit it remotely over the network, without any privileges and without user interaction. Microsoft has not reported exploitation in the wild and rates exploitation as more likely. The EPSS model estimates a 1.20% probability of exploitation activity in the next 30 days, higher than 69% of all scored vulnerabilities. Microsoft released the fix on 8 July 2025 in the July 2025 Patch Tuesday, delivered through 7 security updates (KB5060531, KB5060526, KB5060842, KB5060118 and more). It affects 13 products in 2 product families (Windows, ESU).
Key facts
- CVE ID
- CVE-2025-49735
- Severity
- High CVSS 8.1
- Microsoft severity
- Critical
- Impact
- Remote Code Execution
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- More Likely
- Weakness
- CWE-416
- EPSS
- 1.20% (percentile 69%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- July 2025 Patch Tuesday
- Product families
- Windows, ESU
CVSS score and vector
Microsoft scores CVE-2025-49735 at 8.1 (temporal 7.1) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | High |
| Integrity impact | High |
| Availability impact | High |
| Exploit code maturity | Unproven |
| Remediation level | Official fix |
| Report confidence | Confirmed |
Description
Use after free in Windows KDC Proxy Service (KPSSVC) allows an unauthorized attacker to execute code over a network.
Frequently asked questions (Microsoft)
Are all Windows Servers affected by this vulnerability?
This vulnerability only affects Windows Servers that are configured as a [MS-KKDCP]: Kerberos Key Distribution Center (KDC) Proxy Protocol server. Domain controllers are not affected.
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to win a race condition.
How could an attacker exploit this vulnerability?
An unauthenticated attacker could use a specially crafted application to leverage a cryptographic protocol vulnerability in Kerberos Key Distribution Center Proxy Service to perform remote code execution against the target.
Affected products (13)
Windows
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2019 | KB5060531 | Security Update | 10.0.17763.7434 | Yes |
| Windows Server 2019 (Server Core installation) | KB5060531 | Security Update | 10.0.17763.7434 | Yes |
| Windows Server 2022 | KB5060526 | Security Update | 10.0.20348.3807 | Yes |
| Windows Server 2022 (Server Core installation) | KB5060526 | Security Update | 10.0.20348.3807 | Yes |
| Windows Server 2025 (Server Core installation) | KB5060842 | Security Update | 10.0.26200.4349 | Yes |
| Windows Server 2022, 23H2 Edition (Server Core installation) | KB5060118 | Security Update | 10.0.25398.1665 | Yes |
| Windows Server 2025 | KB5060842 | Security Update | 10.0.26200.4349 | Yes |
| Windows Server 2016 | KB5061010 | Security Update | 10.0.14393.8148 | Yes |
| Windows Server 2016 (Server Core installation) | KB5061010 | Security Update | 10.0.14393.8148 | Yes |
ESU
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2012 | KB5061059 | Monthly Rollup | 6.2.9200.25522 | Yes |
| Windows Server 2012 (Server Core installation) | KB5061059 | Monthly Rollup | 6.2.9200.25522 | Yes |
| Windows Server 2012 R2 | KB5061018 | Monthly Rollup | 6.3.9600.22620 | Yes |
| Windows Server 2012 R2 (Server Core installation) | KB5061018 | Monthly Rollup | 6.3.9600.22620 | Yes |
Security updates (7)
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 8.1 (HIGH)
- NVD weakness
- CWE-416
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| windows server 2012 | all listed versions |
| windows server 2012 r2 | all listed versions |
| windows server 2016 | before 10.0.14393.8148 |
| windows server 2019 | before 10.0.17763.7434 |
| windows server 2022 | before 10.0.20348.3807 |
| windows server 2022 23h2 | before 10.0.25398.1665 |
| windows server 2025 | before 10.0.26100.4349 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-49735 (Vendor Advisory)
Acknowledgments
- ʌ!ɔ⊥ojv with Kunlun Lab
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. | |
| 1.1 | Information published. This CVE was addressed by updates that were released in June 2025, but the CVE was inadvertently omitted from the June 2025 Security Updates. This is an informational change only. Customers who have already installed the June 2025 updates do not need to take any further action. | |
| 1.2 | Corrected Download and Article links in the Security Updates table. This is an informational change only. | |
| 1.3 | Corrected Download and Article links in the Security Updates table. This is an informational change only. |