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HIGH severity

CVE-2021-3910 — cfrpki

HIGHFix: cloudflare/cfrpki@76f0f7a

CVE-2021-3910 is a high-severity (CVSS 7.5) 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.

NUL character in ROA causes OctoRPKI to crash

Also known asGHSA-5mxh-2qfv-4g7jGO-2022-0251
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs69th percentile — riskier than 69% of all scored CVEsHighest risk
0.06%0.64%1.22%1.80%0.6%1.2%May 26Sep 26Nov 26

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

How urgent is this, really

Where this sits among everything scored

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

OctoRPKI crashes when encountering a repository that returns an invalid ROA (just an encoded NUL (\0) character).

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
< 1.4.0
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-2021-3910 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

OctoRPKI crashes when encountering a repository that returns an invalid ROA (just an encoded `NUL` (`\0`) character). ## 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-2021-3910: cfrpki — Fixed in 1.4.0