CVE-2021-3761
7.5 · HIGHOverview
CVE-2021-3761 is a high-severity vulnerability affecting cloudflare octorpki. It was published on September 9, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Any CA issuer in the RPKI can trick OctoRPKI prior to 1.3.0 into emitting an invalid VRP "MaxLength" value, causing RTR sessions to terminate. An attacker can use this to disable RPKI Origin Validation in a victim network (for example AS 13335 - Cloudflare) prior to launching a BGP hijack which during normal operations would be rejected as "RPKI invalid". Additionally, in certain deployments RTR session flapping in and of itself also could cause BGP routing churn, causing availability issues.
Remediation
Check the references section for vendor advisories and patches from cloudflare. Update octorpki to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| cloudflare | octorpki | >= 0, < 1.3.0 | Affected |
Frequently Asked Questions
What is CVE-2021-3761?
CVE-2021-3761 is a high-severity vulnerability affecting cloudflare octorpki. It was published on September 9, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2021-3761?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-3761?
Check the references section for vendor advisories and patches from cloudflare. Update octorpki to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-3761?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-3761 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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