# CVE-2026-53524

## Summary

- **CVE ID:** CVE-2026-53524
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-409
- **Published:** Aug 21, 2026
- **Last Modified:** Aug 24, 2026

## 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

- weechat — weechat (>= 4.3.0, < 4.9.1)

## References

- [CNA](https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.27%
- **EPSS Percentile:** 18.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._