CVE-2018-15756
HIGHCVE-2018-15756 is a high-severity (CVSS 7.5) vulnerability in org.springframework:spring-core. O3 Security confirms whether CVE-2018-15756 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Denial of Service in Spring Framework
Real-World Exposure
org.springframework:spring-core☕org.springframework:spring-core☕org.springframework:spring-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Spring Framework, version 5.1, versions 5.0.x prior to 5.0.10, versions 4.3.x prior to 4.3.20, and older unsupported versions on the 4.2.x branch provide support for range requests when serving static resources through the ResourceHttpRequestHandler, or starting in 5.0 when an annotated controller returns an org.springframework.core.io.Resource. A malicious user (or attacker) can add a range header with a high number of ranges, or with wide ranges that overlap, or both, for a denial of service attack. This vulnerability affects applications that depend on either spring-webmvc or spring-webflux. Such applications must also have a registration for serving static resources (e.g. JS, CSS, images, and others), or have an annotated controller that returns an org.springframework.core.io.Resource. Spring Boot applications that depend on spring-boot-starter-web or spring-boot-starter-webflux are ready to serve static resources out of the box and are therefore vulnerable.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.springframework:spring-core | ≥ 5.1.0.RELEASE&&< 5.1.1.RELEASE | 5.1.1.RELEASE |
| ☕Maven | org.springframework:spring-core | ≥ 5.0.0.RELEASE&&< 5.0.10.RELEASE | 5.0.10.RELEASE |
| ☕Maven | org.springframework:spring-core | ≥ 4.2.0.RELEASE&&< 4.3.20.RELEASE | 4.3.20.RELEASE |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework:spring-core. 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 org.springframework:spring-core to 5.1.1.RELEASE or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-15756 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-2018-15756 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-2018-15756. 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-2018-15756 in your dependencies?
O3 detects CVE-2018-15756 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.