Summary
AnyCable: Telemetry Subsystem Contains Hardcoded Authentication Token and Transmits CLI Arguments Including Secrets
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
- Read
telemetry/config.goin the public repo to findauthToken = "secret". - Set up a DNS spoof for
telemetry.anycable.iopointing to an attacker-controlled server. - Start anycable-go with
--secret=my-production-secret. - The server sends a POST to the attacker's endpoint with the telemetry JSON payload. The
clusterFingerprintfield contains data derived from rawos.Argsincluding--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.
Credentials are embedded in source code or a binary, making them accessible to anyone who can read the artifact. Typical impact: unauthorized access using the static credential.
CVE-2026-63406 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.6.15); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
- Remove the hardcoded
authTokenfrom source; generate or require operator configuration at build time or deployment time. 2. RemoveanycableCLIArgs()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.
Frequently Asked Questions
- What is CVE-2026-63406? CVE-2026-63406 is a medium-severity use of hard-coded credentials vulnerability in github.com/anycable/anycable (go), affecting versions <= 1.6.14. It is fixed in 1.6.15. Credentials are embedded in source code or a binary, making them accessible to anyone who can read the artifact.
- How severe is CVE-2026-63406? CVE-2026-63406 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/anycable/anycable are affected by CVE-2026-63406? github.com/anycable/anycable (go) versions <= 1.6.14 is affected.
- Is there a fix for CVE-2026-63406? Yes. CVE-2026-63406 is fixed in 1.6.15. Upgrade to this version or later.
- Is CVE-2026-63406 exploitable, and should I be worried? Whether CVE-2026-63406 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-63406 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-63406? Upgrade
github.com/anycable/anycableto 1.6.15 or later.