Summary
distribution catalog API endpoint can lead to OOM via malicious user input
Workarounds
There is no way to work around this issue without patching. Restrict access to the affected API endpoint: see the recommendations section.
References
/v2/_catalog endpoint accepts a parameter to control the maximum amount of records returned (query string: n).
When not given the default n=100 is used. The server trusts that n has an acceptable value, however when using a
maliciously large value, it allocates an array/slice of n of strings before filling the slice with data.
This behaviour was introduced ~7yrs ago [1].
Recommendation
The /v2/_catalog endpoint was designed specifically to do registry syncs with search or other API systems. Such an endpoint would create a lot of load on the backend system, due to overfetch required to serve a request in certain implementations.
Because of this, we strongly recommend keeping this API endpoint behind heightened privilege and avoiding leaving it exposed to the internet.
For more information
If you have any questions or comments about this advisory:
- Open an issue in distribution repository
- Email us at [email protected]
[1] faulty commit
Impact
Systems that run distribution built after a specific commit running on memory-restricted environments can suffer from denial of service by a crafted malicious /v2/_catalog API endpoint request.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
CVE-2023-2253 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 (2.8.2-beta.1); 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.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Upgrade to at least 2.8.2-beta.1 if you are running v2.8.x release. If you use the code from the main branch, update at least to the commit after f55a6552b006a381d9167e328808565dd2bf77dc.
Frequently Asked Questions
- What is CVE-2023-2253? CVE-2023-2253 is a high-severity allocation of resources without limits or throttling vulnerability in github.com/docker/distribution (go), affecting versions < 2.8.2-beta.1. It is fixed in 2.8.2-beta.1. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- How severe is CVE-2023-2253? CVE-2023-2253 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.
- Which versions of github.com/docker/distribution are affected by CVE-2023-2253? github.com/docker/distribution (go) versions < 2.8.2-beta.1 is affected.
- Is there a fix for CVE-2023-2253? Yes. CVE-2023-2253 is fixed in 2.8.2-beta.1. Upgrade to this version or later.
- Is CVE-2023-2253 exploitable, and should I be worried? Whether CVE-2023-2253 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-2023-2253 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-2023-2253? Upgrade
github.com/docker/distributionto 2.8.2-beta.1 or later.