CVE-2021-32740

Workarounds

The vulnerability can be avoided by only creating Template objects from trusted sources that have been validated not to produce catastrophic backtracking.

References

• https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS
• https://cwe.mitre.org/data/definitions/1333.html
• https://www.regular-expressions.info/catastrophic.html

For more information

If you have any questions or comments about this advisory:

• Open an issue

Within the URI template implementation in Addressable, a maliciously crafted template may result in uncontrolled resource consumption, leading to denial of service when matched against a URI. In typical usage, templates would not normally be read from untrusted user input, but nonetheless, no previous security advisory for Addressable has cautioned against doing this. Users of the parsing capabilities in Addressable but not the URI template capabilities are unaffected.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2021-32740 has a CVSS score of 7.5 (High). 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 (2.8.0); upgrading removes the vulnerable code path.

Kodem intelligence

The vulnerability was introduced in version 2.3.0 (previously yanked) and has been present in all subsequent versions up to, and including, 2.7.0. It is fixed in version 2.8.0.

1. What is CVE-2021-32740? CVE-2021-32740 is a high-severity uncontrolled resource consumption vulnerability in addressable (rubygems), affecting versions >= 2.3.0, <= 2.7.0. It is fixed in 2.8.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2021-32740? CVE-2021-32740 has a CVSS score of 7.5 (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.
3. Which versions of addressable are affected by CVE-2021-32740? addressable (rubygems) versions >= 2.3.0, <= 2.7.0 is affected.
4. Is there a fix for CVE-2021-32740? Yes. CVE-2021-32740 is fixed in 2.8.0. Upgrade to this version or later.
5. Is CVE-2021-32740 exploitable, and should I be worried? Whether CVE-2021-32740 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-2021-32740 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-2021-32740? Upgrade addressable to 2.8.0 or later.