What is CVE-2021-29435?

CVE-2021-29435 is a high-severity cross-site request forgery (CSRF) vulnerability in trestle-auth (rubygems), affecting versions >= 0.4.0, < 0.4.2. It is fixed in 0.4.2. A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones.

How severe is CVE-2021-29435?

CVE-2021-29435 has a CVSS score of 8.1 (High). 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 trestle-auth are affected by CVE-2021-29435?

trestle-auth (rubygems) versions >= 0.4.0, < 0.4.2 is affected.

Is there a fix for CVE-2021-29435?

Yes. CVE-2021-29435 is fixed in 0.4.2. Upgrade to this version or later.

Is CVE-2021-29435 exploitable, and should I be worried?

Whether CVE-2021-29435 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.

What actually determines whether CVE-2021-29435 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-2021-29435?

Upgrade trestle-auth to 0.4.2 or later.

CVE-2021-29435 in trestle-auth

Q: How severe is CVE-2021-29435?

CVE-2021-29435 has a CVSS score of 8.1 (High). 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.

Q: Which versions of trestle-auth are affected by CVE-2021-29435?

trestle-auth (rubygems) versions >= 0.4.0, < 0.4.2 is affected.

Q: Is there a fix for CVE-2021-29435?

Yes. CVE-2021-29435 is fixed in 0.4.2. Upgrade to this version or later.

Q: Is CVE-2021-29435 exploitable, and should I be worried?

Whether CVE-2021-29435 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.

Q: What actually determines whether CVE-2021-29435 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.

Q: How do I fix CVE-2021-29435?

Upgrade trestle-auth to 0.4.2 or later.

Summary

Cross-Site Request Forgery (CSRF) in trestle-auth

For more information

If you have any questions or comments about this advisory:

Open an issue in trestle-auth
Email the maintainer at [email protected]

Impact

A vulnerability in trestle-auth versions 0.4.0 and 0.4.1 allows an attacker to create a form that will bypass Rails' built-in CSRF protection when submitted by a victim with a trestle-auth admin session. This potentially allows an attacker to alter protected data, including admin account credentials.

A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones. Typical impact: state-changing actions performed as the victim without their consent.

CVE-2021-29435 has a CVSS score of 8.1 (High). 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 (0.4.2); upgrading removes the vulnerable code path.

Affected versions

trestle-auth (>= 0.4.0, < 0.4.2)

Security releases

trestle-auth → 0.4.2 (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

The vulnerability has been fixed in trestle-auth 0.4.2 released to RubyGems.

Frequently Asked Questions

What is CVE-2021-29435? CVE-2021-29435 is a high-severity cross-site request forgery (CSRF) vulnerability in trestle-auth (rubygems), affecting versions >= 0.4.0, < 0.4.2. It is fixed in 0.4.2. A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones.
How severe is CVE-2021-29435? CVE-2021-29435 has a CVSS score of 8.1 (High). 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 trestle-auth are affected by CVE-2021-29435? trestle-auth (rubygems) versions >= 0.4.0, < 0.4.2 is affected.
Is there a fix for CVE-2021-29435? Yes. CVE-2021-29435 is fixed in 0.4.2. Upgrade to this version or later.
Is CVE-2021-29435 exploitable, and should I be worried? Whether CVE-2021-29435 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-2021-29435 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-2021-29435? Upgrade trestle-auth to 0.4.2 or later.