CVE-2016-0034
Microsoft Silverlight · Browsers and web engines
Microsoft Silverlight Runtime Remote Code Execution Vulnerability
At a glance
Exploited. Added to CISA’s catalog of exploited vulnerabilities on May 25, 2022.
Used in ransomware attacks, according to CISA.
End-of-life product: no patch is coming. Remove it or isolate it from the network.
Affected product: Microsoft Silverlight (category Browsers and web engines, indicative classification). Name in CISA’s catalog: Microsoft Silverlight.
Microsoft component: IE, MSHTML and Windows web engines (Browser and web engines).
What should I do?
This product has reached end of life: no patch is coming. Remove it or isolate it from the network.
Deadline set by CISA for US federal agencies: 21 days (due June 15, 2022). It only binds those agencies, but it is a useful measure of urgency.
- CVE-2016-0034 in Microsoft’s Security Update Guide
- Microsoft security advisories page (general page, not the advisory for this vulnerability)
- The vendor’s specific advisory is listed in the NVD references: CVE-2016-0034 on the NVD website.
Original text of the required action (CISA)
The impacted products are end-of-life and should be disconnected if still in use.
Timeline
- Vulnerability published Publication date (NVD)
- Exploitation confirmed Added to CISA’s KEV catalog
- CISA deadline Remediation deadline set for US federal agencies
The facts, with their sources
- Exploitation confirmed
- Yes, on May 25, 2022 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Ransomware
- Known use Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Hunt for compromise
- Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA required action
- This product has reached end of life: no patch is coming. Remove it or isolate it from the network. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA deadline
- June 15, 2022, 21 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Microsoft patch
- Not available Source: Security Update Guide, collected September 29, 2026 at 14:57 UTC
- Vulnerability published
- January 13, 2016 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
- Product according to CISA
- Microsoft Silverlight Filed by this site under “Browsers and web engines” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Severity and activity
FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.
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."
Official description from the NVD, collected Sep 29, 2026. CVE® description © The MITRE Corporation.
Microsoft Silverlight mishandles negative offsets during decoding, which allows attackers to execute remote code or cause a denial-of-service (DoS).
Summary from CISA (KEV catalog).
CERT-FR advisories
No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.
Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.
Sources for this page
- CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
- Microsoft Security Update Guide: product, patch.
- NVD (NIST): CVSS severity, publication date, description, vendor references.
- EPSS (FIRST): probability of exploitation.
- CERT-FR: advisories and alerts (in French).
- Brand and category: indicative classification by this site (method).