Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-53524— WeeChat has a Decompression Bomb in Relay WebSocket (DoS)

Quick assessment

Affected
weechat weechat
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

WeeChat（Wee Enhanced Environment for Chat）是一款免费的聊天客户端。在 4.3.0 到 4.9.0 版本中，WeeChat 的 relay 模块的 WebSocket permessage-deflate 解压缩函数 对输出大小没有上限限制。经过身份验证的 relay 用户可以发送一个小的压缩 WebSocket 帧（约 100 字节），该帧在解压缩后会膨胀到数 GB 大小，从而耗尽服务器内存并导致整个 WeeChat 进程崩溃。api 协议启用了 permessage-de

CVSS 6.5 · Medium EPSS 0.27% · P19

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 1

VendorProduct Version RangeStatus
weechat weechat >= 4.3.0, < 4.9.1 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-53524

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
WeeChat has a Decompression Bomb in Relay WebSocket (DoS)
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
对高度压缩数据的处理不恰当(数据放大攻击)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
weechat weechat >= 4.3.0, < 4.9.1 -

II. Public POCs for CVE-2026-53524

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-53524

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-53524 (1)

IV. Related Vulnerabilities

Same product: weechat
Same vendor: weechat
Same weakness: CWE-409

V. Comments for CVE-2026-53524

No comments yet

Leave a comment