Description
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 relay_websocket_inflate() 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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| weechat | weechat | >= 4.3.0, < 4.9.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | weechat | 4.9.3-1 | — |
| Debian 13 | weechat | No fix yet | — |
| Debian 12 | weechat | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | weechat | No fix yet | — |
| Ubuntu 24.04 LTS | weechat | No fix yet | — |
| Ubuntu 22.04 LTS | weechat | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | weechat | No fix yet | — |
| Ubuntu Pro 18.04 LTS | weechat | No fix yet | — |
| Ubuntu Pro 16.04 LTS | weechat | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | weechat | 4.10.0-1.1 | openSUSE-SU-2026:11481-1 |
| openSUSE Leap 16.0 | weechat | 4.10.0-bp160.1.1 | openSUSE-SU-2026:21615-1 |
Advisories 2
- openSUSE-SU-2026:21615-1 Security update for weechat SUSE / openSUSE Security Updates · Aug 23, 2026
- openSUSE-SU-2026:11481-1 weechat-4.10.0-1.1 on GA media SUSE / openSUSE Security Updates · Aug 10, 2026