Event forgery via unchecked signed request bodies
Published Sep 18, 2026 · Updated Sep 18, 2026
Authentication bypass in AnyCable before 1.6.15 allows remote attackers to broadcast arbitrary events through the Pusher REST API. The Handler trusts the signed body_md5 query value without hashing the received body, then handleEvents parses and broadcasts the substituted body; it also accepts stale auth_timestamp values. Exploitation requires access to one signed POST request and permits indefinite replay within that application's context, including state changes and attacker-controlled client messages.
Summary
What happened
Authentication bypass in AnyCable before 1.6.15 allows remote attackers to broadcast arbitrary events through the Pusher REST API. The Handler trusts the signed body_md5 query value without hashing the received body, then handleEvents parses and broadcasts the substituted body; it also accepts stale auth_timestamp values. Exploitation requires access to one signed POST request and permits indefinite replay within that application's context, including state changes and attacker-controlled client messages.
The record
- CVE
- CVE-2026-63405
- Published
- Sep 18, 2026
- Updated
- Sep 18, 2026
- Vendor
- AnyCable
- Product
- AnyCable
- Classifications
- CWE-345, T1659
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 18, 2026CVE publishedPublication date reported by the CVE source.
- Sep 18, 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?
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- Affected versionversion=< 1.6.15
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- Signed-request body-substitution proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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