CVE-2021-43174 — routinator
HIGHCVE-2021-43174 is a high-severity (CVSS 7.5) CWE-1325 vulnerability in routinator. A fix is available for routinator — see the affected versions and patch details below.
Memory exhaustion in routinator
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2021-43174 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
routinatorReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
NLnet Labs Routinator versions 0.9.0 up to and including 0.10.1, support the gzip transfer encoding when querying RRDP repositories. This encoding can be used by an RRDP repository to cause an out-of-memory crash in these versions of Routinator. RRDP uses XML which allows arbitrary amounts of white space in the encoded data. The gzip scheme compresses such white space extremely well, leading to very small compressed files that become huge when being decompressed for further processing, big enough that Routinator runs out of memory when parsing input data waiting for the next XML element.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | routinator | ≥ 0.9.0&&< 0.10.2 | 0.10.2cargo update -p routinator --precise 0.10.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for routinator, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update routinator to 0.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-43174 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2021-43174 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2021-43174. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-43174 in your dependencies?
O3 Security finds CVE-2021-43174 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.