CVE-2025-27221

CVE-2025-27221 is a low-severity security vulnerability in uri (rubygems), affecting versions < 0.11.3. It is fixed in 0.11.3, 0.12.4, 0.13.2, 1.0.3.

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Summary

URI allows for userinfo Leakage in URI#join, URI#merge, and URI#+

There is a possibility for userinfo leakage by in the uri gem.
This vulnerability has been assigned the CVE identifier CVE-2025-27221. We recommend upgrading the uri gem.

Details

The methods URI#join, URI#merge, and URI#+ retained userinfo, such as user:password, even after the host is replaced. When generating a URL to a malicious host from a URL containing secret userinfo using these methods, and having someone access that URL, an unintended userinfo leak could occur.

Please update URI gem to version 0.11.3, 0.12.4, 0.13.2, 1.0.3 or later.

Affected versions

uri gem versions < 0.11.3, 0.12.0 to 0.12.3, 0.13.0, 0.13.1 and 1.0.0 to 1.0.2.

Credits

Thanks to Tsubasa Irisawa (lambdasawa) for discovering this issue.
Also thanks to nobu for additional fixes of this vulnerability.

Impact

CVE-2025-27221 has a CVSS score of 3.2 (Low). The vector is requires local access, 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 (0.11.3, 0.12.4, 0.13.2, 1.0.3); upgrading removes the vulnerable code path.

Affected versions

uri (< 0.11.3) uri (>= 0.12.0, < 0.12.4) uri (>= 0.13.0, < 0.13.2) uri (>= 1.0.0, < 1.0.3)

Security releases

uri → 0.11.3 (rubygems) uri → 0.12.4 (rubygems) uri → 0.13.2 (rubygems) uri → 1.0.3 (rubygems)

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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Remediation advice

Upgrade the following packages to resolve this vulnerability:

uri to 0.11.3 or later; uri to 0.12.4 or later; uri to 0.13.2 or later; uri to 1.0.3 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

  1. What is CVE-2025-27221? CVE-2025-27221 is a low-severity security vulnerability in uri (rubygems), affecting versions < 0.11.3. It is fixed in 0.11.3, 0.12.4, 0.13.2, 1.0.3.
  2. How severe is CVE-2025-27221? CVE-2025-27221 has a CVSS score of 3.2 (Low). 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.
  3. Which versions of uri are affected by CVE-2025-27221? uri (rubygems) versions < 0.11.3 is affected.
  4. Is there a fix for CVE-2025-27221? Yes. CVE-2025-27221 is fixed in 0.11.3, 0.12.4, 0.13.2, 1.0.3. Upgrade to this version or later.
  5. Is CVE-2025-27221 exploitable, and should I be worried? Whether CVE-2025-27221 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
  6. What actually determines whether CVE-2025-27221 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.
  7. How do I fix CVE-2025-27221?
    • Upgrade uri to 0.11.3 or later
    • Upgrade uri to 0.12.4 or later
    • Upgrade uri to 0.13.2 or later
    • Upgrade uri to 1.0.3 or later

Other vulnerabilities in uri

CVE-IDSeverityPackage summary
CVE-2025-61594Lowuri: URI Credential Leakage Bypass over CVE-2025-27221CVE-2023-36617Mediumuri: URI gem has ReDoS vulnerabilityCVE-2023-28755Highuri: Ruby URI component ReDoS issue

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