CVE-2026-53525

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 (weechat_strcasecmp 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 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechat_strcasecmp 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 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechat_strcasecmp 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 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechat_strcasecmp 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 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechat_strcasecmp 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 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechat_strcasecmp 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.

Decompression Bomb in Relay WebSocket (DoS). (CVE-2026-53524) Non-Constant-Time Password Hash Comparison in Relay Authentication. (CVE-2026-53525)

These are all security issues fixed in the weechat-4.10.0-1.1 package on the GA media of openSUSE Tumbleweed.

This update for weechat fixes the following issues:

Changes in weechat:

• Update to 4.10.0:

  Added

  • core: add command /theme (#1338)
  • core: add built-in "light" theme, applied automatically on first start on light-background terminals (#1338)
  • core: add themable flag on configuration options (#1338)
  • core: add options weechat.look.theme and weechat.look.theme_backup (#1338)
  • api: add function theme_register (#1338)
  • fset: add filter t:themable (#1338)
  • relay/api: add resource GET /api/scripts
  • relay: add option relay.network.unix_socket_permissions (#2317)
  • script: add info "script_languages"

  Changed

  • core: improve speed of /upgrade with a lot of buffers and lines (#2338, #2339, #2341)
  • core: improve speed of display of long words in chat area (#2336)
  • core: add condition on connected relay api clients in default value of option weechat.look.hotlist_add_conditions
  • core: add /mute in default command for key Alt+= (toggle filters)
  • api: change type of parameter "pos_option_name" to "const char **" in function config_search_with_string
  • relay/api: add field "last_read_line_id" in GET /api/buffers

  Fixed

  • core: fix infinite loop when option weechat.look.read_marker_string is set to a string with a width of zero (#2337)
  • core: fix option weechat.look.color_real_white not applied when color is "white" on 16+ colors terminals (#1742)
  • core: fix buffer overflow in connection to SOCKS5 proxy (#2325)
  • api: fix infinite loop in function string_replace when the search string is empty
  • api: do not free dynamic string on error in function string_dyn_concat
  • irc: fix tag in message with list of names when joining a channel
  • fset: remove error displayed in core buffer when clicking with the mouse below the last option displayed
  • guile, lua, perl, python, ruby, tcl: fix conversion of dates in the API functions
  • irc: fix conversion of dates in received messages

  Security

  • core: fix buffer overflow in display of time in chat area with a custom time format (#2342)
  • core: fix integer overflow in size calculation when evaluating "${hide:...}" and "${base_encode:...}" (#2335)
  • core: fix possible buffer overflow in command /color alias (#2330)
  • core: fix possible buffer overflow in list of commands displayed by /help (#2330)
  • irc: fix heap use-after-free when a batched message causes a disconnection from the server (GHSA-rfmh-3r7f-jpx5)
  • irc: fix stack buffer overflow when splitting a JOIN message with a large list of channels and keys (GHSA-q2xg-9ggx-77mr)
  • irc: limit size of data received from the server to prevent memory exhaustion
  • irc: fix out-of-bounds read on incoming DCC command with a quoted filename ending the message (#2322)
  • logger: fix path traversal in log file name when a buffer local variable contains the char used internally to protect directory separators (#2340)
  • relay: fix use-after-free and double free on remote buffer (GHSA-hx59-4hq9-6vmw)
  • relay: fix authentication bypass with the "plain" password hash algorithm (GHSA-68ff-gq39-pqjm)
  • relay: limit size of decompressed websocket frame with permessage-deflate to prevent memory exhaustion (GHSA-v2v4-45wm-5cr3, CVE-2026-53524)
  • relay: limit size of received websocket frame and HTTP body to prevent memory exhaustion
  • relay: limit size of partial message received while reading an HTTP request to prevent memory exhaustion
  • relay: fix timing attack on password authentication (GHSA-vhv8-g2r9-cwcc, CVE-2026-53525)
  • relay: fix out-of-bounds read in dump of data (#2324)
  • relay/api: fix memory leak in resources "handshake", "input" and "completion" (GHSA-wmpc-m6g9-fwj8)
  • relay: fix read of uncompressed websocket frame (#2331)
  • api, relay: fix timing attack on TOTP validation (GHSA-vhv8-g2r9-cwcc, CVE-2026-53525)
  • xfer: replace directory…