WeeChat vulnerabilities

WeeChat before 1.7.1 allows a remote crash by sending a filename via DCC to the IRC plugin. This occurs in the irc_ctcp_dcc_filename_without_quotes function during quote removal, leading to a buffer overflow.

WeeChat versions 0.3.1 through 4.9.0 use non-constant-time string comparison functions (weechat_strcasecmp and strcmp) to verify password hashes and plaintext passwords in relay authentication. An attacker can exploit timing differences to extract the server-computed hash character by character, then authenticate without knowing the password. Version 4.9.1 fixes the issue.

WeeChat versions 4.3.0 through 4.9.0 have a vulnerability in the WebSocket permessage-deflate decompression function relay_websocket_inflate() in the relay module, which has no upper bound on output size. An authenticated relay user can send a small compressed WebSocket frame (~100 bytes) that decompresses to gigabytes, exhausting all server memory and crashing the entire WeeChat process.