CVE-2022-3212 is a high-severity (CVSS 7.5) CWE-770 vulnerability in axum-core. 2 public exploit references exist, so weaponization risk is real. A fix is available for axum-core — see the affected versions and patch details below.
axum-core has no default limit put on request bodies
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-2022-3212 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 378,567 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
axum-core🦀axum-coreReal-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
<bytes::Bytes as axum_core::extract::FromRequest>::from_request would not, by default, set a limit for the size of the request body. That meant if a malicious peer would send a very large (or infinite) body your server might run out of memory and crash.
This also applies to these extractors which used Bytes::from_request internally:
axum::extract::Formaxum::extract::JsonString
The fix is also in axum-core 0.3.0.rc.2 but 0.3.0.rc.1 is vulnerable.
Because axum depends on axum-core it is vulnerable as well. The vulnerable versions of axum are <= 0.5.15 and 0.6.0.rc.1. axum >= 0.5.16 and >= 0.6.0.rc.2 does have the fix and are not vulnerable.
The patched versions will set a 2 MB limit by default.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | axum-core | all versions | 0.2.8cargo update -p axum-core --precise 0.2.8 |
| 🦀crates.io | axum-core | ≥ 0.3.0-rc.1&&< 0.3.0-rc.2 | 0.3.0-rc.2cargo update -p axum-core --precise 0.3.0-rc.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for axum-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update axum-core to 0.2.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-3212 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-2022-3212 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-3212. 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-2022-3212 in your dependencies?
O3 Security finds CVE-2022-3212 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.