What’s Vulnerable › Vulnerabilities

CVE-2026-63405: AnyCable: Pusher REST API Does Not Verify Request Body MD5 Enabling Signed-Request Replay with Arbitrary Body

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-18 · updated 2026-09-24
• Weakness: CWE-345

Description

AnyCable is a realtime server for reliable two-way communication that supports any backend. Prior to 1.6.15, the Pusher-compatible REST API in pusher/http.go includes the caller-supplied body_md5 value in the HMAC input but does not calculate the digest of the received request body or compare it with the signed value. An attacker who obtains a legitimate signed POST request can retain its query parameters and auth_signature while replacing the body, causing Handler and handleEvents to accept and broadcast attacker-selected event content. The absence of an auth_timestamp freshness check also allows the captured signature to be replayed indefinitely. This can forge server-side events, modify application state, or deliver attacker-controlled messages to WebSocket clients within the signed request's application context. This issue is fixed in version 1.6.15.

Affected products

• anycable: before 1.6.15

References

• https://github.com/anycable/anycable/commit/d2cbadec792f038f4695c84a65c0d957b0fde72c
• https://github.com/anycable/anycable/releases/tag/v1.6.15
• https://github.com/anycable/anycable/security/advisories/GHSA-5p54-whvp-x327
• https://github.com/anycable/anycable/security/advisories/GHSA-5p54-whvp-x327

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