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CVE-2026-57973 Microsoft CVE debrief

CVE-2026-57973 is a time-of-check time-of-use (toctou) race condition vulnerability in the Windows Subsystem for Linux. An authorized attacker could exploit this vulnerability locally to perform tampering. The vulnerability has a CVSS score of 6.3 and a severity rating of MEDIUM. This type of vulnerability can be particularly problematic in multi-user environments or where local access is not tightly controlled. The vulnerability exists due to a race condition between the time of check and the time of use, allowing an attacker to manipulate the system in unintended ways. System administrators and security teams should be aware of this vulnerability and take necessary precautions to mitigate the risk.

Vendor
Microsoft
Product
Windows Subsystem for Linux (WSL2)
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-20
Advisory published
2026-07-14
Advisory updated
2026-07-20

Who should care

System administrators and security teams responsible for Windows Subsystem for Linux installations should be aware of this vulnerability and take necessary precautions to mitigate the risk. This includes reviewing system configurations, monitoring for suspicious activity, and applying patches or updates as soon as possible. Additionally, teams should consider implementing compensating controls to detect and prevent potential exploitation attempts.

Technical summary

The vulnerability exists in the Windows Subsystem for Linux due to a time-of-check time-of-use (toctou) race condition. This allows an authorized attacker to perform tampering locally. The CVSS vector for this vulnerability is CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N. The vulnerability can be exploited by an attacker with local access to the system, potentially leading to unauthorized modifications or tampering with system resources.

Defensive priority

Medium priority should be given to patching or mitigating this vulnerability, as it could allow an authorized attacker to perform tampering locally. However, the priority may need to be adjusted based on the specific environment and the potential impact of exploitation.

Recommended defensive actions

  • Apply the vendor patch or update as soon as possible
  • Implement compensating controls to monitor and detect potential exploitation attempts
  • Conduct a thorough inventory of affected systems and prioritize patching
  • Consider implementing additional security measures to restrict local access to sensitive systems
  • Review relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record was published on 2026-07-14T18:18:35.460Z and was last modified on 2026-07-20T18:39:35.017Z. The NVD entry is currently Analyzed. The vulnerability details are based on the information available from the CVE record and NVD entry. However, the accuracy of this information is limited by the evidence available and may not reflect the full scope or impact of the vulnerability. Defenders should verify the affected systems and take necessary precautions to mitigate the risk.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-14T18:18:35.460Z and has not been modified since then. The NVD entry is currently Analyzed.