Microsoft Windows User Profile Service Privilege Escalation Vulnerability

HIGH 7.8EXPLOITED (CISA KEV)CVE-2021-34484 · Published 12/08/2021 · updated 10/08/2026

Microsoft Windows User Profile Service Privilege Escalation Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 31/03/2022. Patch affected systems as an emergency.

In short

CVE-2021-34484 is a HIGH (CVSS 7.8) vulnerability.
Exploited in the wild: CISA added it to the KEV catalog on 31/03/2022.
Chance of exploitation in the next 30 days (EPSS): 21.8%, higher than 97.6% of all vulnerabilities.
No patched version is listed yet: follow the vendor's advisory in References.

Package	Affected versions	Patched versions
Windows Microsoft	Versions not published yet (product named by CISA KEV)

Description

Windows User Profile Service Elevation of Privilege Vulnerability

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34484 · Patch
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34484 · Patch
cisa.gov/known-exploited-vulnerabilities-catalog · US Government Resource
CISA KEV · CVE-2021-34484

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