Spring Reactor Core vulnerabilities

Latest Spring Reactor Core CVEs

Newest publication first

1. CVE-2026-47863 Reactor Core bufferTimeout fair-backpressure pipeline permanently hangs when upstream delivers items during an active flush

   Published 2026-08-26

   High·CVSS 7.5 EPSS 0.40%

   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

2. CVE-2026-47857 Reactor Core windowTimeout fair-backpressure stream hang due to 20-bit index wrap-around

   Published 2026-08-26

   Medium·CVSS 5.9 EPSS 0.37%

   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

Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.