CVE-2026-47857

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

State: Published
Severity: 5.9 Medium
Published: Aug 26, 2026
Updated: Aug 27, 2026
Reserved: May 20, 2026

Description

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

Scores

CVSS	Score	Vector	Source
3.1	5.9 Medium	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H	vmware

Weaknesses

CWE-190 Integer Overflow or Wraparound

Affected Products

Product	Versions
Reactor CoreSpring	3.8.0 through 3.8.6Affected 3.5.0 through 3.7.19Affected 3.4.41 and earlierAffected

References

https://spring.io/security/cve-2026-47857

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