Ubuntu Security Notice 4684-1 - Laszlo Ersek discovered that EDK II incorrectly validated certain signed images. An attacker could possibly use this issue with a specially crafted image to cause EDK II to hang, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. It was discovered that EDK II incorrectly parsed signed PKCS #7 data. An attacker could use this issue to cause EDK II to crash, resulting in a denial of service, or possibly execute arbitrary code. Various other issues were also addressed.
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