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MEDIUM severity

CVE-2026-41847 — spring-webflux

MEDIUM

CVE-2026-41847 is a medium-severity (CVSS 4.8) CWE-284 vulnerability in org.springframework:spring-webflux. No vendor fix is recorded yet; mitigation options are listed below.

Spring Framework Security Filter Bypass in WebFlux Kotlin Router DSL

Published
Updated
Affected
1 pkg
Patched
See advisory
Exploits
None indexed
Exploitation data as of Oct 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-2026-41847.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk-0.10%
Lower risk than most CVEs6th percentile — riskier than 6% of all scored CVEsHighest risk
0.00%0.25%0.51%0.76%0.2%0.2%0.2%0.3%0.2%Jul 26Sep 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
☕org.springframework:spring-webflux

Real-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 may be vulnerable to a security bypass when using the Kotlin Router DSL.

Affected versions: Spring Framework 5.3.0 through 5.3.48.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
☕Mavenorg.springframework:spring-webfluxall versionsNo fix

Affected Products

1 product · 1 configurations
Application
spring frameworkvmware
≥ 5.3.0 && < 5.3.49
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    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.

  2. Remediation status

    No patched version of org.springframework:spring-webflux has shipped for CVE-2026-41847 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

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 HatModerate

Red Hat ships Spring WebFlux in Fuse 7. The affected version is set to AFFECTED/DEFER as the CVSS score (4.8) is below the 7.0 threshold. This flaw only affects applications using the Kotlin Router DSL.

Workaround published by Red Hat
This vulnerability only applies when using Kotlin Router DSL. Applications using Java-based routing are not affected.
Source: Red Hat security advisory for CVE-2026-41847 (CC BY 4.0)

Frequently Asked Questions

Spring 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.
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CVE-2026-41847: spring-webflux (Medium 4.8)