CVE-2026-53524Network attack vector

Authenticated process crash via unbounded WebSocket decompression

Published Aug 21, 2026 · Updated Aug 21, 2026

Denial of service in WeeChat 4.3.0 through 4.9.0 allows remote authenticated users to crash the process via a compressed relay frame. The relay_websocket_inflate() loop doubles its destination buffer without an output cap while inflating permessage-deflate data. The API relay must be enabled and reachable with valid credentials; one small frame can exhaust memory and terminate all sessions in the process.

CVSS severity6.5
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in WeeChat 4.3.0 through 4.9.0 allows remote authenticated users to crash the process via a compressed relay frame. The relay_websocket_inflate() loop doubles its destination buffer without an output cap while inflating permessage-deflate data. The API relay must be enabled and reachable with valid credentials; one small frame can exhaust memory and terminate all sessions in the process.

The record

CVE
CVE-2026-53524
Published
Aug 21, 2026
Updated
Aug 21, 2026
Vendor
WeeChat
Product
WeeChat
Classifications
CWE-409, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 4.3.0, < 4.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

WeeChat · WeeChatversion=>= 4.3.0, < 4.9.1

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-409Improper Handling of Highly Compressed Data (Data Amplification)
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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