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-------------------- Start of forwarded message -------------------- Date: Sat, 5 Sep 2026 19:31:16 +0200 From: Sébastien Helleu <flashcode () flashtux org> To: weechat-security () nongnu org Subject: Security vulnerabilities fixed in WeeChat 4.10.1
Hi all,
Six security vulnerabilities have been fixed in WeeChat 4.10.1, which was released on September 5th, 2026:
- WSA-2026-15: [Xfer] Write of DCC file received outside of configured download path. - WSA-2026-16: [Xfer] Missing size limit for the unterminated Xfer chat message. - WSA-2026-17: [Xfer] Bypass of user authorization for start of DCC file transfer. - WSA-2026-18: [Relay] Missing size limit for the unterminated Relay text message received from a client. - WSA-2026-19: [Relay] Missing rejection of invalid websocket frames. - WSA-2026-20: [Relay] Missing size limit of data queued for sending to clients.
For more information, see the security page: https://weechat.org/doc/weechat/security/
-- Sébastien Helleu
web: weechat.org / flashtux.org irc: FlashCode @ irc.libera.chat
-------------------- End of forwarded message --------------------
WeeChat (Wee Enhanced Environment for Chat) is a free chat client. In versions 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechatstrcasecmp and strcmp) to verify password hashes and plaintext passwords. An attacker can exploit timing differences to extract the server-computed hash character by character, then authenticate using the correct hash without knowing the password. Version 4.9.1 fixes the issue.
WeeChat (Wee Enhanced Environment for Chat) is a free chat client. In versions 4.3.0 through 4.9.0, the WeeChat relay module's WebSocket permessage-deflate decompression function relaywebsocketinflate() 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. The api protocol enables permessage-deflate and requires authentication before WebSocket upgrade. Version 4.9.1 patches the issue.
Latest version: 4.10.1
End of life: 8/2/2026, Latest version: 4.9.5
End of life: 3/29/2026, Latest version: 4.8.2
End of life: 11/30/2025, Latest version: 4.7.2
End of life: 7/19/2025, Latest version: 4.6.3
End of life: 3/23/2025, Latest version: 4.5.2
End of life: 3/23/2025, Latest version: 4.5.2
End of life: 12/15/2024, Latest version: 4.4.4
End of life: 12/15/2024, Latest version: 4.4.4
WeeChat before 4.4.2 has an integer overflow and resultant buffer overflow at core/core-string.c when there are more than two billion items in a list. This affects stringfreesplitshared , stringfreesplit, stringfreesplitcommand, and stringfreesplittags.
End of life: 8/17/2024, Latest version: 4.3.6
End of life: 8/17/2024, Latest version: 4.3.6
End of life: 5/26/2024, Latest version: 4.2.3
End of life: 5/26/2024, Latest version: 4.2.3
End of life: 1/21/2024, Latest version: 4.1.3
End of life: 1/21/2024, Latest version: 4.1.3
End of life: 10/15/2023, Latest version: 4.0.8
End of life: 10/15/2023, Latest version: 4.0.8
End of life: 6/24/2023, Latest version: 3.8
End of life: 6/24/2023, Latest version: 3.8
End of life: 1/8/2023, Latest version: 3.7.1
End of life: 1/8/2023, Latest version: 3.7.1
End of life: 10/9/2022, Latest version: 3.6
End of life: 10/9/2022, Latest version: 3.6
WeeChat (aka Wee Enhanced Environment for Chat) 3.2 to 3.4 before 3.4.1 does not properly verify the TLS certificate of the server, after certain GnuTLS options are changed, which allows man-in-the-middle attackers to spoof a TLS chat server via an arbitrary certificate. NOTE: this only affects situations where weechat.network.gnutlscasystem or weechat.network.gnutlscauser is changed without a WeeChat restart.
End of life: 7/10/2022, Latest version: 3.5
End of life: 7/10/2022, Latest version: 3.5