Race Condition Affecting io.projectreactor:reactor-core package, versions [,3.8.7)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-IOPROJECTREACTOR-19267102
- published26 Aug 2026
- disclosed20 Aug 2026
- creditSage Pierce
Introduced: 20 Aug 2026
NewCVE-2026-47863 (opens in a new tab)How to fix?
Upgrade io.projectreactor:reactor-core to version 3.8.7 or higher.
Overview
Affected versions of this package are vulnerable to Race Condition in the Flux.bufferTimeout process with fairBackpressure enabled when a race condition occurs between flushing buffered items and the arrival of new upstream items. An attacker can cause the stream to hang indefinitely and exhaust resources by manipulating the timing of upstream item delivery to trigger this race condition.