Fix out-of-bounds read on malformed uuencode "begin" line#55
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The three uudecode loops (mailparse_msg_extract_uue, _enum_uue and mailparse_uudecode_all) matched a "begin " prefix (6 bytes) and then unconditionally read the filename at buffer[10], assuming the "begin <mode> <name>" layout. A short line such as "begin 644\n" (strlen 10) put buffer[10] at or past the NUL terminator, reading into stack/heap garbage. The subsequent trailing-whitespace trim (`while (isspace(origfilename[len-1]))`) could also underflow to origfilename[-1] when the filename was empty. Clamp the filename offset to the actual line length and guard the trim loop with len > 0. Also cast the isspace() argument to unsigned char to avoid UB on bytes with the high bit set.
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The three uudecode loops (
mailparse_msg_extract_uue,_enum_uue,mailparse_uudecode_all) matched a 6-bytebeginprefix and then read the filename unconditionally atbuffer[10], assuming abegin <mode> <name>layout. A short line such asbegin 644\n(strlen 10) putsbuffer[10]at or past the NUL terminator, reading into stack garbage; the trailing-whitespace trim could also underflow toorigfilename[-1]on an empty filename. Both are reachable from attacker-controlled message bodies.Clamp the filename offset to the actual line length (
&buffer[len > 10 ? 10 : len]), guard the trim loop withlen > 0, and cast theisspace()argument tounsigned char.