{"id":"CVE-2026-53524","title":"WeeChat (Wee Enhanced Environment for Chat) is a free chat client","summary":"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 siz…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-409"],"published":"2026-08-21","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:06:39.057","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53524","references":[{"url":"https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3","label":"security-advisories@github.com"},{"url":"https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd"],"epss":0.00268,"epssPercentile":0.19136,"ingestedAt":"2026-09-09T21:22:45.549Z","slug":"CVE-2026-53524","body":"## Overview\n\nWeeChat (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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}