CVE-2016-4121

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.

Published: 2016-06-16 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-4121 is rated High Risk (77.4/100): CVSS Critical severity, with high exploitation likelihood (EPSS 15.87%, 95th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +10.64% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2016-4121

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-27 5.23% 15.87% +10.64%
2 2026-03-04 4.50% 5.23% +0.73%
3 2026-03-01 — 4.50% —

Full EPSS history (39 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-4121

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2016-4121

OS Trackers for CVE-2016-4121

vendor priority summary link
gentoo normal CVE-2016-4121: 1 GLSA(s) (201606-08), 1 atom(s) (www-plugins/adobe-flash); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-4121
redhat critical — https://access.redhat.com/security/cve/CVE-2016-4121
ubuntu medium CVE-2016-4121 medium priority: Ubuntu including 2 source packages (adobe-flashplugin, flashplugin-nonfree), 10 status rows across 5 suites (precise, trusty, upstream, wily, xenial): released 8, needs-triage 2. https://ubuntu.com/security/CVE-2016-4121

NVD evaluator notes for CVE-2016-4121

Comment: CWE-416: Use After Free

Affected software / configurations for CVE-2016-4121

Vendor Product Version Raw CPE
adobe flash_player <= 21.0.0.241 cpe:2.3:a:adobe:flash_player:*:*:*:*:*:edge:*:*
adobe flash_player <= 21.0.0.241 cpe:2.3:a:adobe:flash_player:*:*:*:*:*:internet_explorer:*:*
adobe flash_player <= 18.0.0.343 cpe:2.3:a:adobe:flash_player:*:*:*:*:esr:*:*:*
adobe air_sdk_\&_compiler <= 21.0.0.198 cpe:2.3:a:adobe:air_sdk_\&_compiler:*:*:*:*:*:*:*:*
adobe air_sdk <= 21.0.0.198 cpe:2.3:a:adobe:air_sdk:*:*:*:*:*:*:*:*
adobe flash_player <= 11.2.202.616 cpe:2.3:a:adobe:flash_player:*:*:*:*:*:*:*:*
adobe flash_player <= 21.0.0.216 cpe:2.3:a:adobe:flash_player:*:*:*:*:*:chrome:*:*
adobe flash_player_desktop_runtime <= 21.0.0.226 cpe:2.3:a:adobe:flash_player_desktop_runtime:*:*:*:*:*:*:*:*
adobe air_desktop_runtime <= 21.0.0.198 cpe:2.3:a:adobe:air_desktop_runtime:*:*:*:*:*:*:*:*

References for CVE-2016-4121

cvelogic Threat Intelligence