CVE-2024-39908
MEDIUMCVE-2024-39908 is a medium-severity (CVSS 4.3) Uncontrolled Resource Consumption vulnerability in rexml. O3 Security confirms whether CVE-2024-39908 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Denial of service in REXML
Blast Radius
rexmlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
REXML is an XML toolkit for Ruby. The REXML gem before 3.3.1 has some DoS vulnerabilities when it parses an XML that has many specific characters such as <, 0 and %>. If you need to parse untrusted XMLs, you many be impacted to these vulnerabilities. The REXML gem 3.3.2 or later include the patches to fix these vulnerabilities. Users are advised to upgrade. Users unable to upgrade should avoid parsing untrusted XML strings.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rexml | all versions | 3.3.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rexml. 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 rexml to 3.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-39908 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-2024-39908 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-2024-39908. 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-2024-39908 in your dependencies?
O3 detects CVE-2024-39908 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.