CVE-2011-4320
CVE-2011-4320 is a CWE-399 vulnerability in ejabberd. O3 Security confirms whether CVE-2011-4320 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Ejabberd DoS via malformed stanza
Blast Radius
ejabberd💧ejabberdReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
The mod_pubsub module (mod_pubsub.erl) in ejabberd 2.1.8 and 3.0.0-alpha-3 allows remote authenticated users to cause a denial of service (infinite loop) via a stanza with a publish tag that lacks a node attribute.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | ejabberd | all versions | 2.1.9 |
| 💧Hex | ejabberd | ≥ 3.0.0-alpha-1&&< 3.0.0-alpha-4 | 3.0.0-alpha-4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ejabberd. 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 ejabberd to 2.1.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-4320 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-2011-4320 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-2011-4320. 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-2011-4320 in your dependencies?
O3 detects CVE-2011-4320 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.