CVE-2026-47857mediumCWE-190

CVE-2026-47857: medium-severity vulnerability in Spring Reactor Core

Reactor Core windowTimeout fair-backpressure stream hang due to 20-bit index wrap-around

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5.9epss 0.4%
In Reactor Core, applications that use the Flux.windowTimeout operator with fairBackpressure enabled are vulnerable to a Denial of Service (DoS) condition. Reactor Core 3.8.0 - 3.8.6 Reactor Core 3.5.0 - 3.7.19 Reactor Core 3.4.41 and earlier
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
Spring · Reactor Core
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CVE-2026-47863MEDIUMReactor Core bufferTimeout fair-backpressure pipeline permanently hangs when upstream delivers items during an active flushEPSS 0.4%