CVE-2021-26431

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

1.17% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 66.9% of scored records. A rank, not a probability.

NVD base score

7.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-08-10.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-08-12 18:11Z5 YR AGO

Last updated

2026-08-10 15:10Z2 MO AGO

Reserved

2021-01-29

Assigning CNA

microsoft

Record state

PUBLISHED

Severity

High (CVSS 7.8)

CNA CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Weaknesses

No CWE assigned

Data version

5.2

Document digest

bbd438bb8b16f231014322dab742da513b6b59efbfec01ff34930c5216447b89

• msrc.microsoft.comWindows Recovery Environment Agent Elevation of Privilege Vulnerabilityhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26431vendor-advisorypatch
• portal.msrc.microsoft.comhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26431x_refsource_MISC
• www.zerodayinitiative.comhttps://www.zerodayinitiative.com/advisories/ZDI-21-1053/x_refsource_MISC