CVE-2016-4121

9.8 CRITICAL 10% exploit odds Fix listed Memory safety Browser & mail

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 10.0% chance of exploitation in the next 30 days (EPSS). Higher than most.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2016-06-16 14:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 00:46 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 10.0% in the next 30 days (EPSS).
Severity: 9.8 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2016-06-16 14:59 UTC
Last modified: 2026-06-17 00:46 UTC
Exploit probability: 10.0% · EPSS, next 30 days
Weakness: CWE-416 · Use after free
Record status: Modified

Affected

Adobe Flash Player ≤ 21.0.0.241
Adobe Flash Player ≤ 18.0.0.343
Adobe Air Sdk \& Compiler ≤ 21.0.0.198
Adobe Air Sdk ≤ 21.0.0.198
Adobe Flash Player ≤ 11.2.202.616
Adobe Flash Player ≤ 21.0.0.216
Adobe Flash Player Desktop Runtime ≤ 21.0.0.226
Adobe Air Desktop Runtime ≤ 21.0.0.198

Attack profile CVSS 3.1 · 9.8

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2016-4121.md and follow it. Check whether this project is affected by CVE-2016-4121. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record