K-9 Mail v5.600 can include the original quoted HTML code of a specially crafted, benign looking, email within (digitally signed) reply messages. The quoted part can contain conditional statements that show completely different text if opened in a different email client. This can be abused by an attacker to obtain valid S/MIME or PGP signatures for arbitrary content to be displayed to a third party. NOTE: the vendor states "We don't plan to take any action because of this."
Software security is not security software. Here we're concerned with topics like authentication, access control, confidentiality, cryptography, and privilege management.
Link | Tags |
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https://github.com/k9mail/k-9/issues/3925 | third party advisory |