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MEDIUM severity

CVE-2021-3911 — cfrpki

MEDIUMFix: cloudflare/cfrpki@2882307

CVE-2021-3911 is a medium-severity (CVSS 6.5) Improper Input Validation vulnerability in github.com/cloudflare/cfrpki. A fix is available for github.com/cloudflare/cfrpki — see the affected versions and patch details below.

Misconfigured IP address field in ROA leads to OctoRPKI crash

Also known asGHSA-w6ww-fmfx-2x22GO-2022-0252
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk
0.05%0.50%0.96%1.41%0.6%0.9%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-3911 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐹github.com/cloudflare/cfrpki

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

If the ROA that a repository returns contains too many bits for the IP address then OctoRPKI will crash.

Patches

For more information

If you have any questions or comments about this advisory email us at [email protected]

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/cloudflare/cfrpkiall versions1.4.0go get github.com/cloudflare/cfrpki@v1.4.0

Affected Products

2 products · 2 configurations
Application
octorpkicloudflare
< 1.3.0
range
OS
debian linuxdebian
1 version
11.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/cloudflare/cfrpki, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/cloudflare/cfrpki to 1.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-3911 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

If the ROA that a repository returns contains too many bits for the IP address then OctoRPKI will crash. ## Patches ## For more information If you have any questions or comments about this advisory email us at [email protected]
O3 Security · Impact-Aware SCA

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CVE-2021-3911: cfrpki — Fixed in 1.4.0