CVE-2026-53524
WeeChat has a Decompression Bomb in Relay WebSocket (DoS)
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-409 |
| Vendor | weechat |
| Product | weechat |
| Published | Aug 21, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
weechat / weechat
>= 4.3.0, < 4.9.1