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Known exploited · Adobe

CVE-2018-4878: Adobe Flash Player Use-After-Free Vulnerability

What it is

Adobe Flash Player contains a use-after-free vulnerability that could allow for code execution.

Added November 3, 2021Due May 3, 2022CISA KEV catalog 2026.10.01

Vendor
Adobe
Product
Flash Player
Added to KEV
November 3, 2021
CISA due date
May 3, 2022
Ransomware use
Known

What CISA requires

The impacted product is end-of-life and should be disconnected if still in use.

Forensic triage

No

What to do now

  1. Find every instance of Flash Player you run, including the forgotten ones, and check its version against the vendor advisory.
  2. Apply the vendor's fix or mitigation, before May 3, 2022 if you are bound by CISA's deadline, sooner if it faces the internet.
  3. Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.

References

CVE-2018-4878 in the National Vulnerability Database

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.