CVE-2026-53524

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.

CVSS v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3
https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3

Configurations

No configuration.

History

14 Oct 2026, 19:10

Type	Values Removed	Values Added
Summary		(es) WeeChat (Wee Enhanced Environment for Chat) es un cliente de chat gratuito. En las versiones 4.3.0 a 4.9.0, la función de descompresión permessage-deflate de WebSocket del módulo de retransmisión de WeeChat, relay_websocket_inflate(), no tiene un límite superior en el tamaño de salida. Un usuario de retransmisión autenticado puede enviar una pequeña trama WebSocket comprimida (~100 bytes) que se descomprime a gigabytes, agotando toda la memoria del servidor y bloqueando todo el proceso de WeeChat. El protocolo API habilita permessage-deflate y requiere autenticación antes de la actualización de WebSocket. La versión 4.9.1 corrige el problema.

Information

Published : 2026-08-21 23:16

Updated : 2026-10-14 19:10

NVD link : CVE-2026-53524

Mitre link : CVE-2026-53524

CVE.ORG link : CVE-2026-53524

JSON object : View

Products Affected

No product.

CWE

CWE-409

Improper Handling of Highly Compressed Data (Data Amplification)

{"id": "CVE-2026-53524", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-53524", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-24T20:09:05.967952Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 2.8}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "weechat", "product": "weechat", "versions": [{"status": "affected", "version": ">= 4.3.0, < 4.9.1"}]}]}], "published": "2026-08-21T23:16:26.213", "references": [{"url": "https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3", "source": "security-advisories@github.com"}, {"url": "https://github.com/weechat/weechat/security/advisories/GHSA-v2v4-45wm-5cr3", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-409"}]}], "descriptions": [{"lang": "en", "value": "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."}, {"lang": "es", "value": "WeeChat (Wee Enhanced Environment for Chat) es un cliente de chat gratuito. En las versiones 4.3.0 a 4.9.0, la funci\u00f3n de descompresi\u00f3n permessage-deflate de WebSocket del m\u00f3dulo de retransmisi\u00f3n de WeeChat, relay_websocket_inflate(), no tiene un l\u00edmite superior en el tama\u00f1o de salida. Un usuario de retransmisi\u00f3n autenticado puede enviar una peque\u00f1a trama WebSocket comprimida (~100 bytes) que se descomprime a gigabytes, agotando toda la memoria del servidor y bloqueando todo el proceso de WeeChat. El protocolo API habilita permessage-deflate y requiere autenticaci\u00f3n antes de la actualizaci\u00f3n de WebSocket. La versi\u00f3n 4.9.1 corrige el problema."}], "lastModified": "2026-10-14T19:10:00.297", "sourceIdentifier": "security-advisories@github.com"}