CVE-2021-4235
MEDIUMCVSS 5.5/10EPSS 0.41%
Last modified
CVE-2021-4235 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. Due to unbounded alias chasing, a maliciously crafted YAML file can cause the system to consume significant system resources. If parsing user input, this may be used as a denial of service vector.. EPSS estimates a 0.41% chance of exploitation in the next 30 days.
Description
Due to unbounded alias chasing, a maliciously crafted YAML file can cause the system to consume significant system resources. If parsing user input, this may be used as a denial of service vector.
Metrics
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Yaml Project | Yaml | < 2.2.3 |
References
- https://github.com/go-yaml/yaml/commit/bb4e33bf68bf89cad44d386192cbed201f35b241Patch, Third Party Advisory
- https://github.com/go-yaml/yaml/pull/375Exploit, Patch, Third Party Advisory
- https://pkg.go.dev/vuln/GO-2021-0061Third Party Advisory
- https://github.com/go-yaml/yaml/commit/bb4e33bf68bf89cad44d386192cbed201f35b241Patch, Third Party Advisory
- https://github.com/go-yaml/yaml/pull/375Exploit, Patch, Third Party Advisory
- https://pkg.go.dev/vuln/GO-2021-0061Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-4235?
Due to unbounded alias chasing, a maliciously crafted YAML file can cause the system to consume significant system resources. If parsing user input, this may be used as a denial of service vector.
How severe is CVE-2021-4235?
CVE-2021-4235 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.41% probability of exploitation in the next 30 days.
How do I fix CVE-2021-4235?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-4235?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST