Reactor Core 3.8.x bufferTimeout DoS (fairBackpressure)
CVE-2026-47863 Published on August 26, 2026

Reactor Core bufferTimeout fair-backpressure pipeline permanently hangs when upstream delivers items during an active flush
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

NVD

Vulnerability Analysis

CVE-2026-47863 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
HIGH
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Products Associated with CVE-2026-47863

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VMware Spring Framework
 

Affected Versions

Spring Reactor Core: