CVE-2021-44716
HIGHCVE-2021-44716 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in golang.org/x/net/http2. O3 Security confirms whether CVE-2021-44716 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
golang.org/x/net/http2 allows uncontrolled memory consumption
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-2021-44716 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 365,017 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
golang.org/x/net/http2Real-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
net/http in Go before 1.16.12 and 1.17.x before 1.17.5 allows uncontrolled memory consumption in the header canonicalization cache via HTTP/2 requests.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | golang.org/x/net/http2 | all versions | 0.0.0-20211209124913-491a49abca63 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/net/http2. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update golang.org/x/net/http2 to 0.0.0-20211209124913-491a49abca63 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-44716 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 pinpoints whether CVE-2021-44716 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2021-44716. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
For OpenShift Container Platform, OpenShift Virtualization, Red Hat Quay and OpenShift distributed tracing the most an attacker can possibly achieve by exploiting this vulnerability is to crash a container, temporarily impacting availability of one or more services. Therefore impact is rated Moderate. In its default…
Frequently Asked Questions
Is CVE-2021-44716 in your dependencies?
O3 detects CVE-2021-44716 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.