EUVD-2026-66828
GHSA-5jp2-w3vg-5w3x
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Network vector and no-auth match remote trigger; AC:H reflects the non-default fairBackpressure configuration requirement; A:H for full DoS with no C/I impact.
Primary rating from Vendor (vmware).
CVSS VectorVendor: vmware
Lifecycle Timeline
2DescriptionCVE.org
In Reactor Core, applications that use the Flux.bufferTimeout operator with fairBackpressure enabled are vulnerable to a Denial of Service (DoS) condition. Reactor Core 3.8.0 - 3.8.6 Reactor Core 3.7.19 and earlier
AnalysisAI
Flux.bufferTimeout operator in Spring Reactor Core can be driven into a Denial of Service condition when the fairBackpressure option is explicitly enabled, affecting versions 3.8.0-3.8.6 and 3.7.19 and earlier. Remote unauthenticated attackers who can reach the application's reactive endpoints may exploit the pathological backpressure state to fully disrupt availability. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the target application to explicitly invoke the Flux.bufferTimeout reactive operator with the fairBackpressure parameter set to true - this is a non-default configuration that must be deliberately coded into the application. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 score of 5.9 (Medium) reflects AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - network-reachable and unauthenticated but with high attack complexity, no confidentiality or integrity impact, and full availability loss. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade Reactor Core to a patched release per the vendor advisory at https://spring.io/security/cve-2026-47863. … Detailed patch versions, workarounds, and compensating controls in full report. |
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External POC / Exploit Code
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