What’s Vulnerable › Vulnerabilities
CVE-2026-47863: Reactor Core bufferTimeout fair-backpressure pipeline permanently hangs when upstream delivers items during an active flush
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-27 · updated 2026-09-01
- Weakness: CWE-835
Description
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
Affected products
- Spring Reactor Core: from 3.5.7 before 3.7.20; from 3.8.0 before 3.8.6.1 — fixed in 3.7.20, 3.8.6.1
How to fix
Upgrade to a fixed version: Spring Reactor Core 3.7.20, 3.8.6.1. Check the vendor advisory for mitigations.
References
Get alerted when CVE-2026-47863 or the next vulnerability affects your stack