VDB

CVE-2026-53524

CVE-2026-53524 PUBLISHED CVSS 6.5 MEDIUM

Reported by GitHub_M · Published August 21, 2026

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.

Risk Scores

CVSS 3.1
6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

VendorProductVersions
weechatweechat>= 4.3.0, < 4.9.1
weechatweechat>= 4.3.0, < 4.9.1

Timeline

  • Aug 9, 2026 CVE Published
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