CVE-2026-63406

AnyCable is a realtime server for reliable two-way communication that supports any backend. Prior to 1.6.15, the telemetry subsystem in telemetry/config.go enables tracking with a hardcoded public authToken, while clusterFingerprint in telemetry/telemetry.go reads the full configuration file and raw os.Args returned by anycableCLIArgs, including values supplied through --secret, --jwt_secret, and --http_rpc_secret. These inputs are passed to generateDigest, where sha256.New produces the hexadecimal fingerprint that is sent as telemetry. The available source therefore does not show raw credentials leaving the process or establish the advisory's claimed confidentiality loss, although the stable fingerprint is derived from secret-bearing configuration and the default telemetry client uses publicly known authentication material. This issue is fixed in version 1.6.15.

AnyCable is a realtime server for reliable two-way communication that supports any backend. Prior to 1.6.15, the telemetry subsystem in telemetry/config.go enables tracking with a hardcoded public authToken, while clusterFingerprint in telemetry/telemetry.go reads the full configuration file and raw os.Args returned by anycableCLIArgs, including values supplied through --secret, --jwt_secret, and --http_rpc_secret. These inputs are passed to generateDigest, where sha256.New produces the hexadecimal fingerprint that is sent as telemetry. The available source therefore does not show raw credentials leaving the process or establish the advisory's claimed confidentiality loss, although the stable fingerprint is derived from secret-bearing configuration and the default telemetry client uses publicly known authentication material. This issue is fixed in version 1.6.15.

Summary

The telemetry subsystem embeds a hardcoded auth token ("secret") in the public source and transmits raw CLI arguments—including --secret, --jwt_secret, and --http_rpc_secret values—to a third-party telemetry endpoint.

Details

In telemetry/config.go line 12, var authToken = "secret" is committed in the public repository and used to authenticate to https://telemetry.anycable.io. In telemetry/telemetry.go, clusterFingerprint() (line 320) calls both anycableFileConfig(c.ConfigFilePath) (line 333), which reads the full TOML config file contents, and anycableCLIArgs() (line 402), which reads os.Args[1:] verbatim—including any --secret=..., --jwt_secret=..., --http_rpc_secret=... arguments. Both raw values are passed to generateDigest() (line 373), meaning the actual secret strings flow through the code path and are included in telemetry data sent to the third-party server. Since the hardcoded authToken = "secret" is public, any attacker who can perform DNS hijacking or is positioned on the network path can intercept and read the telemetry payload containing operator credentials.

PoC

1. Read telemetry/config.go in the public repo to find authToken = "secret".
2. Set up a DNS spoof for telemetry.anycable.io pointing to an attacker-controlled server.
3. Start anycable-go with --secret=my-production-secret.
4. The server sends a POST to the attacker's endpoint with the telemetry JSON payload. The clusterFingerprint field contains data derived from raw os.Args including --secret=my-production-secret.

Impact

In MITM/DNS-hijack scenarios, production secrets (JWT secrets, broadcast keys, RPC auth) are exposed to third parties. The hardcoded authToken = "secret" provides no protection since it is known to anyone reading the open-source code.

Fix

1. Remove the hardcoded authToken from source; generate or require operator configuration at build time or deployment time. 2. Remove anycableCLIArgs() from the fingerprint computation, or sanitize it to exclude values of secret-bearing flags before hashing. 3. Add a documented opt-out mechanism for telemetry.

AnyCable is a realtime server for reliable two-way communication that supports any backend. Prior to 1.6.15, the telemetry subsystem in telemetry/config.go enables tracking with a hardcoded public authToken, while clusterFingerprint in telemetry/telemetry.go reads the full configuration file and raw os.Args returned by anycableCLIArgs, including values supplied through --secret, --jwt_secret, and --http_rpc_secret. These inputs are passed to generateDigest, where sha256.New produces the hexadecimal fingerprint that is sent as telemetry. The available source therefore does not show raw credentials leaving the process or establish the advisory's claimed confidentiality loss, although the stable fingerprint is derived from secret-bearing configuration and the default telemetry client uses publicly known authentication material. This issue is fixed in version 1.6.15.

AnyCable is a realtime server for reliable two-way communication that supports any backend. Prior to 1.6.15, the telemetry subsystem in telemetry/config.go enables tracking with a hardcoded public authToken, while clusterFingerprint in telemetry/telemetry.go reads the full configuration file and raw os.Args returned by anycableCLIArgs, including values supplied through --secret, --jwt_secret, and --http_rpc_secret. These inputs are passed to generateDigest, where sha256.New produces the hexadecimal fingerprint that is sent as telemetry. The available source therefore does not show raw credentials leaving the process or establish the advisory's claimed confidentiality loss, although the stable fingerprint is derived from secret-bearing configuration and the default telemetry client uses publicly known authentication material. This issue is fixed in version 1.6.15.

Summary

The telemetry subsystem embeds a hardcoded auth token ("secret") in the public source and transmits raw CLI arguments—including --secret, --jwt_secret, and --http_rpc_secret values—to a third-party telemetry endpoint.

Details

In telemetry/config.go line 12, var authToken = "secret" is committed in the public repository and used to authenticate to https://telemetry.anycable.io. In telemetry/telemetry.go, clusterFingerprint() (line 320) calls both anycableFileConfig(c.ConfigFilePath) (line 333), which reads the full TOML config file contents, and anycableCLIArgs() (line 402), which reads os.Args[1:] verbatim—including any --secret=..., --jwt_secret=..., --http_rpc_secret=... arguments. Both raw values are passed to generateDigest() (line 373), meaning the actual secret strings flow through the code path and are included in telemetry data sent to the third-party server. Since the hardcoded authToken = "secret" is public, any attacker who can perform DNS hijacking or is positioned on the network path can intercept and read the telemetry payload containing operator credentials.

PoC

1. Read telemetry/config.go in the public repo to find authToken = "secret".
2. Set up a DNS spoof for telemetry.anycable.io pointing to an attacker-controlled server.
3. Start anycable-go with --secret=my-production-secret.
4. The server sends a POST to the attacker's endpoint with the telemetry JSON payload. The clusterFingerprint field contains data derived from raw os.Args including --secret=my-production-secret.

Impact

In MITM/DNS-hijack scenarios, production secrets (JWT secrets, broadcast keys, RPC auth) are exposed to third parties. The hardcoded authToken = "secret" provides no protection since it is known to anyone reading the open-source code.

Fix

1. Remove the hardcoded authToken from source; generate or require operator configuration at build time or deployment time. 2. Remove anycableCLIArgs() from the fingerprint computation, or sanitize it to exclude values of secret-bearing flags before hashing. 3. Add a documented opt-out mechanism for telemetry.

AnyCable: Telemetry Subsystem Contains Hardcoded Authentication Token and Transmits CLI Arguments Including Secrets in github.com/anycable/anycable-go.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: github.com/anycable/anycable-go before v1.6.15.