CVE-2023-49090

CarrierWave Content-Type allowlist bypass vulnerability, possibly leading to XSS

Workarounds

When validating with allowlisted_content_type? in CarrierWave::Uploader::ContentTypeAllowlist , forward match(\A) the Content-Type set in content_type_allowlist, preventing unintentional permission of text/html;image/png when you want to allow only image/png in content_type_allowlist.

References

OWASP - File Upload Cheat Sheet

CarrierWave::Uploader::ContentTypeAllowlist has a Content-Type allowlist bypass vulnerability, possibly leading to XSS.

The validation in allowlisted_content_type? determines Content-Type permissions by performing a partial match.
If the content_type argument of allowlisted_content_type? is passed a value crafted by the attacker, Content-Types not included in the content_type_allowlist will be allowed.

In addition, by setting the Content-Type configured by the attacker at the time of file delivery, it is possible to cause XSS on the user's browser when the uploaded file is opened.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2023-49090 has a CVSS score of 6.8 (Medium). The vector is network-reachable, low 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 (3.0.5, 2.2.5); upgrading removes the vulnerable code path.

Kodem intelligence

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Upgrade to 3.0.5 or 2.2.5.

1. What is CVE-2023-49090? CVE-2023-49090 is a medium-severity cross-site scripting (XSS) vulnerability in carrierwave (rubygems), affecting versions >= 3.0.0, < 3.0.5. It is fixed in 3.0.5, 2.2.5. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2023-49090? CVE-2023-49090 has a CVSS score of 6.8 (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.
3. Which versions of carrierwave are affected by CVE-2023-49090? carrierwave (rubygems) versions >= 3.0.0, < 3.0.5 is affected.
4. Is there a fix for CVE-2023-49090? Yes. CVE-2023-49090 is fixed in 3.0.5, 2.2.5. Upgrade to this version or later.
5. Is CVE-2023-49090 exploitable, and should I be worried? Whether CVE-2023-49090 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-2023-49090 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-2023-49090?
   • Upgrade carrierwave to 3.0.5 or later
   • Upgrade carrierwave to 2.2.5 or later

Other vulnerabilities in carrierwave