CVE-2026-41840 — spring-webflux
MEDIUMCVE-2026-41840 is a medium-severity (CVSS 5.9) CWE-401 vulnerability in org.springframework:spring-webflux. A fix is available for org.springframework:spring-webflux — see the affected versions and patch details below.
Spring Framework Denial of Service via Multipart Requests in WebFlux
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-41840.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-41840 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 397,508 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
org.springframework:spring-webflux☕org.springframework:spring-webflux☕org.springframework:spring-webflux☕org.springframework:spring-webfluxReal-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 WebFlux applications are vulnerable to Denial of Service (DoS) attacks when processing multipart requests.
Affected versions: Spring Framework 7.0.0 through 7.0.7; 6.2.0 through 6.2.18; 6.1.0 through 6.1.27; 5.3.0 through 5.3.48.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.springframework:spring-webflux | ≥ 7.0.0&&< 7.0.8 | 7.0.8org.springframework:spring-webflux:7.0.8 |
| ☕Maven | org.springframework:spring-webflux | ≥ 6.2.0&&< 6.2.19 | 6.2.19org.springframework:spring-webflux:6.2.19 |
| ☕Maven | org.springframework:spring-webflux | ≥ 6.1.0 | No fix |
| ☕Maven | org.springframework:spring-webflux | all versions | No fix |
Affected Products
spring frameworkvmwareDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework:spring-webflux, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.springframework:spring-webflux to 7.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41840 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat ships Spring WebFlux in Fuse 7. The affected version is set to AFFECTED/DEFER as the CVSS score (5.9) is below the 7.0 threshold for immediate remediation.
No specific mitigation is available. Restrict access to multipart request endpoints where possible.Source: Red Hat security advisory for CVE-2026-41840 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-41840 in your dependencies?
Find it across Maven, including transitive dependencies.