CISA KEV catalog
Confirmed active exploitation.
Listed in CISA's catalog of Known Exploited Vulnerabilities: attackers are using it in real attacks. Patch it with priority.
- Name
- Microsoft Silverlight Runtime Remote Code Execution Vulnerability
- Added to catalog
- Remediation due date (US federal)
- Required action
- The impacted products are end-of-life and should be disconnected if still in use.
Description
Microsoft Silverlight 5 before 5.1.41212.0 mishandles negative offsets during decoding, which allows remote attackers to execute arbitrary code or cause a denial of service (object-header corruption) via a crafted web site, aka "Silverlight Runtime Remote Code Execution Vulnerability."
Affected products
microsoft: silverlight
References5
- docs.microsoft.com/en-us/security-updates/securitybulletins/201… PatchVendor Advisory
- docs.microsoft.com/en-us/security-updates/securitybulletins/201… PatchVendor Advisory
- www.securitytracker.com/id/1034655 Broken LinkThird Party AdvisoryVDB Entry
- www.securitytracker.com/id/1034655 Broken LinkThird Party AdvisoryVDB Entry
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=… US Government Resource
Metrics
- CVSS 3.1
-
8.8
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 69% percentile: 99 · as of 8 November 2026
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