CVE-2018-1000883 is a medium-severity (CVSS 6.5) Improper Input Validation vulnerability in plug. O3 Security confirms whether CVE-2018-1000883 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Header Injection
Real-World Exposure
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Description
Elixir Plug Plug version All contains a Header Injection vulnerability in Connection that can result in Given a cookie value, Headers can be added. This attack appear to be exploitable via Crafting a value to be sent as a cookie. This vulnerability appears to have been fixed in >= 1.3.5 or ~> 1.2.5 or ~> 1.1.9 or ~> 1.0.6.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | plug | all versions | 1.0.6 |
| 💧Hex | plug | ≥ 1.1.0&&< 1.1.9 | 1.1.9 |
| 💧Hex | plug | ≥ 1.2.0&&< 1.2.5 | 1.2.5 |
| 💧Hex | plug | ≥ 1.3.0&&< 1.3.5 | 1.3.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for plug. 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 plug to 1.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1000883 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-2018-1000883 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-2018-1000883. 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-2018-1000883 in your dependencies?
O3 detects CVE-2018-1000883 across Hex dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.