Quantum Secular Labs / Blog / Advisories

CVE-2016-4121: Adobe Flash Player: Use after free

CVE-2016-4121 is rated critical with a CVSS v3.1 base score of 9.8 and affects Adobe Flash Player, along with 4 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

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.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-416: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

Affected products

  • Adobe Flash Player: up to and including 21.0.0.241; up to and including 18.0.0.343; up to and including 11.2.202.616; up to and including 21.0.0.216
  • Adobe Air Sdk & Compiler: up to and including 21.0.0.198
  • Adobe Air Sdk: up to and including 21.0.0.198
  • Adobe Flash Player Desktop Runtime: up to and including 21.0.0.226
  • Adobe Air Desktop Runtime: up to and including 21.0.0.198

References