Bug 2521246 (CVE-2026-53524)

Summary: CVE-2026-53524 weechat: WeeChat: Denial of Service via WebSocket decompression bomb
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in WeeChat. An authenticated user of the relay module's WebSocket functionality can send a small compressed frame that, when decompressed, expands to a significantly larger size. This "decompression bomb" can exhaust all available server memory, leading to a Denial of Service (DoS) by crashing the WeeChat process.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2521989, 2523271, 2521990    
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Description OSIDB Bzimport 2026-08-21 22:31:20 UTC
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.