Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.
High CVSS 7.5
Summary
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.
In-depth triage · Auto channel
No in-depth report has been generated yet (DR-003 v2 AI pipeline is under construction).
Affected products
- :
Lint boundary warnings (2)
The following non-blocking warnings were raised during the lint phase of this triage (e.g. reference URLs not yet on the allowlist). They do not affect entry usability and are disclosed for transparency (see DR-002).
-
REF_URL_NOT_ALLOWLISTEDurl not in allowlist: https://www.vicarius.io/vsociety/posts/cve-2026-20921-detection-script-race-condition-vulnerability-in-windows-smb-server -
REF_URL_NOT_ALLOWLISTEDurl not in allowlist: https://www.vicarius.io/vsociety/posts/cve-2026-20921-remediation-script-race-condition-vulnerability-in-windows-smb-server
Sources
- NVD DATABASE
Original Links
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20921 Vendor Advisory
- https://www.vicarius.io/vsociety/posts/cve-2026-20921-detection-script-race-condition-vulnerability-in-windows-smb-server
- https://www.vicarius.io/vsociety/posts/cve-2026-20921-remediation-script-race-condition-vulnerability-in-windows-smb-server
Timeline
- nvd_ingest NVD