high severity · exploited in the wild · published 2025-02-11
An attacker who already runs code as a normal user can raise their rights to a much higher level and take over the PC. Attackers already use this flaw in the wild.
Fixed in: 10.0.19045.5487, 10.0.20348.3148, 10.0.20348.3207, 10.0.22621.4890, 10.0.22631.4890, 10.0.25398.1425, 10.0.26100.3107, 10.0.26100.3194
CVE: CVE-2025-21391
Source: Microsoft (MSRC)
You are affected if the installed version is older than the fixed version of its release line: 10.0.19045.5487, 10.0.20348.3148, 10.0.20348.3207, 10.0.22621.4890, 10.0.22631.4890, 10.0.25398.1425, 10.0.26100.3107, 10.0.26100.3194. Check the version you have and update to the fixed version of your line or later. The fixed versions are verified against a vendor or advisory source.
FixLane has a reviewed fix procedure for this incident: a read-only check first, then the fix. Ask the Telegram bot, or connect an AI agent to the FixLane MCP server and call get_fix_prompt with incident id 1549 and your operating system.