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
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.
Weakness Type
What is an Infinite Loop Vulnerability?
The program contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. If the loop can be influenced by an attacker, this weakness could allow attackers to consume excessive resources such as CPU or memory.
CVE-2026-47863 has been classified to as an Infinite Loop vulnerability or weakness.
Products Associated with CVE-2026-47863
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Affected Versions
Spring Reactor Core:- Version 3.8.0, <= 3.8.6 is affected.
- Before and including 3.7.19 is affected.