CVE-2026-59324: fluxTransform shared RequestMessageHolder causes cross-message header leakage under async fluxFunction

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% 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-362

Description

When an IntegrationFlow uses .fluxTransform() with an asynchronous/reordering fluxFunction that emits raw payloads, concurrent requests on the same FluxMessageChannel subscription have their reply headers (replyChannel, errorChannel, correlationId, any propagated security/tenant headers) copied from whichever message was most recently consumed upstream. Spring Integration 7.1.0 Spring Integration 7.0.0 - 7.0.5 Spring Integration 6.5.0 - 6.5.10 Spring Integration 6.4.0 - 6.4.12 Spring Integration 5.5.21 and earlier

Affected products

Spring Integration: before 5.5.22; from 6.4.0 before 6.4.13; from 6.5.0 before 6.5.11; from 7.0.0 before 7.0.5.1; from 7.1.0 before 7.1.0.1 — fixed in 5.5.22, 6.4.13, 6.5.11, 7.0.5.1, 7.1.0.1
Spring Integration: from 7.0.0 through 7.0.5; from 6.5.0 through 6.5.10; from 6.4.0 through 6.4.12; through 5.5.21; 7.1.0

How to fix

Upgrade to a fixed version: Spring Integration 5.5.22, 6.4.13, 6.5.11, 7.0.5.1. Check the vendor advisory for mitigations.

References

https://spring.io/security/cve-2026-59324

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