CVE-2026-65679: Windows iSCSI Target Service Remote Code Execution Vulnerability
CVE-2026-65679 is a remote code execution vulnerability in Windows iSCSI Target Service, 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 less likely. The EPSS model estimates a 0.71% probability of exploitation activity in the next 30 days, higher than 54% of all scored vulnerabilities. Microsoft released the fix on 11 August 2026 in the August 2026 Patch Tuesday, delivered through 8 security updates (KB5120238, KB5120242, KB5120229, KB5120233 and more). It affects 16 products in 2 product families (Windows, ESU).
Key facts
- CVE ID
- CVE-2026-65679
- Severity
- High CVSS 8.1
- Microsoft severity
- Critical
- Impact
- Remote Code Execution
- Exploited in the wild
- No
- Publicly disclosed
- No
- Exploitation likelihood
- Less Likely
- Weakness
- CWE-122
- EPSS
- 0.71% (percentile 54%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- August 2026 Patch Tuesday
- Product families
- Windows, ESU
CVSS score and vector
Microsoft scores CVE-2026-65679 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
Heap-based buffer overflow in Windows iSCSI Target Service allows an unauthorized attacker to execute code over a network.
Frequently asked questions (Microsoft)
How could an attacker exploit this vulnerability?
An unauthenticated attacker could exploit this vulnerability by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system. No authentication or user interaction is required..
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 have a deep understanding of the system. Successful exploitation is not guaranteed and depends on a combination of factors that might include the environment, system configuration, and the presence of additional security measures.
Affected products (16)
Windows
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows 10 Version 1809 for 32-bit Systems | KB5120238 | Security Update | 10.0.17763.9121 | Yes |
| Windows 10 Version 1809 for x64-based Systems | KB5120238 | Security Update | 10.0.17763.9121 | Yes |
| Windows Server 2019 | KB5120238 | Security Update | 10.0.17763.9121 | Yes |
| Windows Server 2019 (Server Core installation) | KB5120238 | Security Update | 10.0.17763.9121 | Yes |
| Windows Server 2022 | KB5120242 KB5120229 | Security Update Security Hotpatch Update | 10.0.20348.5499 10.0.20348.5440 | Yes Yes |
| Windows Server 2022 (Server Core installation) | KB5120242 KB5120229 | Security Update Security Hotpatch Update | 10.0.20348.5499 10.0.20348.5440 | Yes Yes |
| Windows Server 2025 (Server Core installation) | KB5120233 KB5120228 | Security Update Security Hotpatch Update | 10.0.26100.33296 10.0.26100.33222 | Yes Yes |
| Windows Server 2025 | KB5120233 KB5120228 | Security Update Security Hotpatch Update | 10.0.26100.33296 10.0.26100.33222 | Yes Yes |
| Windows 10 Version 1607 for 32-bit Systems | KB5120418 | Security Update | 10.0.14393.9418 | Yes |
| Windows 10 Version 1607 for x64-based Systems | KB5120418 | Security Update | 10.0.14393.9418 | Yes |
| Windows Server 2016 | KB5120418 | Security Update | 10.0.14393.9418 | Yes |
| Windows Server 2016 (Server Core installation) | KB5120418 | Security Update | 10.0.14393.9418 | Yes |
ESU
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| Windows Server 2012 | KB5120386 | Monthly Rollup | 6.2.9200.26280 | Yes |
| Windows Server 2012 (Server Core installation) | KB5120386 | Monthly Rollup | 6.2.9200.26280 | Yes |
| Windows Server 2012 R2 | KB5120385 | Monthly Rollup | 6.3.9600.23338 | Yes |
| Windows Server 2012 R2 (Server Core installation) | KB5120385 | Monthly Rollup | 6.3.9600.23338 | Yes |
Security updates (8)
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 8.1 (HIGH)
- NVD weakness
- CWE-122
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| windows 10 1607 (x64) | before 10.0.14393.9418 |
| windows 10 1607 (x86) | before 10.0.14393.9418 |
| windows 10 1809 (x64) | before 10.0.17763.9115 |
| windows 10 1809 (x86) | before 10.0.17763.9115 |
| windows server 2012 | all listed versions |
| windows server 2012 r2 | all listed versions |
| windows server 2016 | before 10.0.14393.9418 |
| windows server 2019 | before 10.0.17763.9115 |
| windows server 2022 | before 10.0.20348.5440 |
| windows server 2025 | before 10.0.26100.33222 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65679 (Vendor Advisory, Patch)
Acknowledgments
- Linzishan & Anemone & Zhiniang Peng (HUST)
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. | |
| 1.1 | Updated the severity of the products in the Security Updates table. This is an informational change only. |