Summary
Phoenix Arbitrary URL Redirect
The Phoenix team designed Phoenix.Controller.redirect/2 to protect against redirects allowing user input to redirect to an external URL where your application code otherwise assumes a local path redirect. This is why the :to option is used for “local” URL redirects and why you must pass the :external option to intentionally allow external URLs to be redirected to. It has been disclosed that carefully crafted user input may be treated by some browsers as an external URL. An attacker can use this vulnerability to aid in social engineering attacks. The most common use would be to create highly believable phishing attacks. For example, the following user input would pass local URL validation, but be treated by Chrome and Firefox as external URLs:http://localhost:4000/?redirect=/\nexample.com
Not all browsers are affected, but latest Chrome and Firefox will issue a get request for example.com and successfully redirect externally
Impact
Untrusted input controls a URL used for redirection, which can forward users to attacker-controlled sites. Typical impact: phishing and credential harvesting via a trusted domain.
CVE-2017-1000163 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. 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 (1.0.6, 1.1.8, 1.2.3); 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.
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phoenix to 1.0.6 or later; phoenix to 1.1.8 or later; phoenix to 1.2.3 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2017-1000163? CVE-2017-1000163 is a medium-severity open redirect vulnerability in phoenix (erlang), affecting versions < 1.0.6. It is fixed in 1.0.6, 1.1.8, 1.2.3. Untrusted input controls a URL used for redirection, which can forward users to attacker-controlled sites.
- How severe is CVE-2017-1000163? CVE-2017-1000163 has a CVSS score of 6.1 (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 phoenix are affected by CVE-2017-1000163? phoenix (erlang) versions < 1.0.6 is affected.
- Is there a fix for CVE-2017-1000163? Yes. CVE-2017-1000163 is fixed in 1.0.6, 1.1.8, 1.2.3. Upgrade to this version or later.
- Is CVE-2017-1000163 exploitable, and should I be worried? Whether CVE-2017-1000163 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-2017-1000163 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-2017-1000163?
- Upgrade
phoenixto 1.0.6 or later - Upgrade
phoenixto 1.1.8 or later - Upgrade
phoenixto 1.2.3 or later
- Upgrade