Spring FrameworkFramework / library · VMware
CVE-2026-41847
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedSpring WebFlux applications may be vulnerable to a security bypass when using the Kotlin Router DSL. Affected versions: Spring Framework 5.3.0 through 5.3.48.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceSpring WebFlux applications using the Kotlin Router DSL are vulnerable to a security bypass. The vulnerability allows attackers to circumvent security checks in the routing layer, potentially accessing protected endpoints or resources they should not have access to.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Spring FrameworkFramework / library
>= 5.3.0, < 5.3.49CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the Spring Framework version in your projectInspect your build configuration file (pom.xml for Maven, build.gradle or build.gradle.kts for Gradle) and locate the spring-framework or spring-webflux dependency. Check the declared version.Affected if The version is 5.3.0 or higher but lower than 5.3.49 (for example, 5.3.48 would be affected)
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Confirm Spring WebFlux is in your dependenciesCheck your build file for the spring-webflux dependency. This vulnerability only affects WebFlux applications.Affected if spring-webflux is present as a dependency in your project
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Verify Kotlin Router DSL usage in your codebaseSearch your source code for Kotlin files containing router {} DSL blocks or imports from org.springframework.web.reactive.function.server. Look for patterns such as 'router { ... }' or 'RouterFunction' definitions.Affected if Kotlin files define routes using the functional routing DSL
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Identify route security configurations that may be bypassedReview your Kotlin router definitions for any route access restrictions, such as routes requiring authentication, authorization checks, or IP-based filters. Check if functional security annotations or custom handlers enforce access control.Affected if Your router definitions include security constraints on certain routes that should restrict access
You are affected if your application uses Spring Framework 5.3.0 through 5.3.48 with Spring WebFlux and Kotlin Router DSL to define routes with access restrictions.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.3.49
Upgrade Spring Framework to version 5.3.49 or later to obtain the security patch. If immediate upgrading is not feasible, review and supplement Router DSL security configurations with additional filters or gateway-level controls.
Spring Framework 5.3.49
- 1. Identify your build configuration file (pom.xml for Maven or build.gradle for Gradle)
- 2. Locate the Spring Framework dependency declaration (spring-webflux)
- 3. Update the version from your current 5.3.x version to 5.3.49
- 4. For Maven: Change <version>5.3.x</version> to <version>5.3.49</version>
- 5. For Gradle: Change implementation('org.springframework:spring-webflux:5.3.x') to implementation('org.springframework:spring-webflux:5.3.49')
- 6. Run your build to verify dependency resolution
- 7. Run your test suite to verify application functionality
- 8. If using Spring Boot, ensure your Spring Boot version is compatible with Spring Framework 5.3.49 (Spring Boot 2.7.x typically uses 5.3.x)
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Spring Framework
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-41847 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-41847 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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