In GnuPG through 2.4.8, armor_filter in g10/armor.c has two increments of an index variable where one is intended, leading to an out-of-bounds write for crafted input.Referenceshttps://gpg.fail/memcpyhttps://news.ycombinator.com/item?id=46403200https://www.openwall.com/lists/oss-security/2025/12/28/5https://github.com/gpg/gnupg/commit/115d138ba599328005c5321c0ef9f00355838ca9https://github.com/gpg/gnupg/blob/ff30683418695f5d2cc9e6cf8c9418e09378ebe4/g10/armor.c#L1305-L1306
