CVE-2021-40083
HIGHCVSS 7.5/10EPSS 1.42%
Last modified
CVE-2021-40083 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).. EPSS estimates a 1.42% chance of exploitation in the next 30 days.
Description
Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Nic | Knot Resolver | < 5.3.2 |
References
- https://gitlab.nic.cz/knot/knot-resolver/-/merge_requests/1169Patch, Third Party Advisory
- https://gitlab.nic.cz/knot/knot-resolver/-/merge_requests/1169Patch, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-40083?
Knot Resolver before 5.3.2 is prone to an assertion failure, triggerable by a remote attacker in an edge case (NSEC3 with too many iterations used for a positive wildcard proof).
How severe is CVE-2021-40083?
CVE-2021-40083 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.42% probability of exploitation in the next 30 days.
How do I fix CVE-2021-40083?
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-2021-40083?
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