Adobes security team published the private PGP key for its [email protected] email account. The key was used exclusively for email correspondence between external security researchers and Adobe security team. Adobe has issued a statement reassuring customers that it doesnt believe any harm was done. An opportunistic hacker could have used the private key to create PGP-signed messages that appeared to really come from Adobe. Furthermore, the key could have been used to unlock messages from researchers who had discovered zero-day vulnerabilities in say Flash Player.”]
Source: https://grahamcluley.com/adobe-security-private-pgp-key/