What is CVE-2021-3908?

CVE-2021-3908 is a medium-severity vulnerability in Cloudflare Octorpki, classified under Uncontrolled Resource Consumption. CVSS score: 5.9/10. Published 2021-11-11.

How severe is CVE-2021-3908?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Resource exhaustion in Cloudflare Octorpki

CVE-2021-3908

OctoRPKI does not limit the depth of a certificate chain, allowing for a CA to create children in an ad-hoc fashion, thereby making tree traversal never end.

Vulnerability class: DoS (Denial of Service)

Published 2021-11-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

Cloudflare Octorpki — versions unspecified
Debian Linux — versions 11.0

Weakness classification (CWE)

References

github.com/cloudflare/cfrpki/security/advisories/GHSA-g5gj-9ggf-9vmq (Third Party Advisory)
www.debian.org/security/2022/dsa-5041 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2021-3908?: CVE-2021-3908 is a medium-severity vulnerability in Cloudflare Octorpki, classified under Uncontrolled Resource Consumption. CVSS score: 5.9/10. Published 2021-11-11.
How severe is CVE-2021-3908?: Medium severity. CVSS v3 base score is 5.9 out of 10.