Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
How likely is exploitation in the next 30 days?
25.3%
EPSS score, percentile 97.9 of all scored records. A probability estimated by FIRST, not a report of exploitation.
How severe?
9.8Critical
CVSS v3.1 base score, given by the CNA
What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Microsoft Windows Server 2012 (Server Core installation)
Status
Versions
Affected
from 6.2.9200.0 to before 6.2.9200.26132
Microsoft Windows Server 2012 R2
Status
Versions
Affected
from 6.3.9600.0 to before 6.3.9600.23228
Microsoft Windows Server 2012 R2 (Server Core installation)
Status
Versions
Affected
from 6.3.9600.0 to before 6.3.9600.23228
Microsoft Windows Server 2016
Status
Versions
Affected
from 10.0.14393.0 to before 10.0.14393.9234
Microsoft Windows Server 2016 (Server Core installation)
Status
Versions
Affected
from 10.0.14393.0 to before 10.0.14393.9234
Microsoft Windows Server 2019
Status
Versions
Affected
from 10.0.17763.0 to before 10.0.17763.8880
Microsoft Windows Server 2019 (Server Core installation)
Status
Versions
Affected
from 10.0.17763.0 to before 10.0.17763.8880
Microsoft Windows Server 2022
Status
Versions
Affected
from 10.0.20348.0 to before 10.0.20348.5256
Microsoft Windows Server 2025
Status
Versions
Affected
from 10.0.26100.0 to before 10.0.26100.32995
Microsoft Windows Server 2025 (Server Core installation)
Status
Versions
Affected
from 10.0.26100.0 to before 10.0.26100.32995
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
Integer overflow or wraparound in Windows HTTP.sys allows an unauthorized attacker to execute code over a network.
Summary: CVE record, as of .
CISA has not added CVE-2026-47291 to its Known Exploited Vulnerabilities (KEV) catalog, as of 28 Oct 2026.
The CVE record was published on 9 Jun 2026.
The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
FIRST's EPSS model puts the probability of exploitation in the next 30 days at 25.3% (percentile 97.9), as of 28 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
HTTP.sys Remote Code Execution Vulnerability
Integer overflow or wraparound in Windows HTTP.sys allows an unauthorized attacker to execute code over a network.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.