Vulnerability Snapshot
CVE-2016-4121 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.
Affected technology: windows_10, windows_8.1, flash_player, mac_os_x, windows, plus 5 other product variants.
Executive Summary
Use-after-free vulnerability in Adobe Flash Player before 18.0.0.352 and 19.x through 21.x before 21.0.0.242 on Windows and OS X and before 11.2.202.621 on Linux allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-1097, CVE-2016-1106, CVE-2016-1107, CVE-2016-1108, CVE-2016-1109, CVE-2016-1110, CVE-2016-4108, and CVE-2016-4110.
Why It Matters
CVE-2016-4121 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9.8/10
Affected Technologies
Vendors: microsoft, adobe, apple, google, linux
Products: windows_10, windows_8.1, flash_player, mac_os_x, windows, air_sdk_\&_compiler, iphone_os, android, air_sdk, linux_kernel, chrome_os, flash_player_desktop_runtime, air_desktop_runtime
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2016-4121 and similar vulnerabilities.
References & Sources
How Vulnios Detects This
Vulnios scans for this vulnerability using Trivy and Grype for CVE matching against your container images and OS package manifests and KEV cross-check that flags any host where this CVE is already on CISA's exploited list. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.
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Affected Products
Sources
Related Threat Alerts
- Critical Vulnerability: CVE-2016-4161 — microsoft, adobe — windows_10, windows_8.1
- Critical Vulnerability: CVE-2016-4120 — microsoft, adobe — windows_10, windows_8.1
- Critical Vulnerability: CVE-2016-4162 — microsoft, adobe — windows_10, windows_8.1
- Critical Vulnerability: CVE-2016-4160 — microsoft, adobe — windows_10, windows_8.1
- Critical Vulnerability: CVE-2016-4163 — microsoft, adobe — windows_10, windows_8.1
Frequently Asked Questions
What is CVE-2016-4121?
CVE-2016-4121 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. Use-after-free vulnerability in Adobe Flash Player before 18.0.0.352 and 19.x through 21.x before 21.0.0.242 on Windows and OS X and before 11.2.202.621 on Linux allows attackers to execute arbitrary
Am I affected?
Check whether your environment runs windows_10, windows_8.1, flash_player, mac_os_x, windows. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.
How urgent is the response?
Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.
How do I remediate?
Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.
Where can I track exploitation activity?
Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2016-4121. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.
How does Vulnios help with this?
Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.
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