CVE-2026-47889: Spring Framework sameSite Attribute Dropped in JettyCoreServerHttpResponse

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 2026-09-10
Weakness: CWE-1275

Description

A WebFlux application running on the Jetty 12 Core reactive adapter serializes response cookies without the sameSite attribute. Spring Framework 7.0.0 - 7.0.8 Spring Framework 6.2.0 - 6.2.19

Affected products

Spring Framework: from 6.2.0 before 6.2.20; from 7.0.0 before 7.0.8.1 — fixed in 6.2.20, 7.0.8.1
Spring Framework: from 7.0.0 through 7.0.8; from 6.2.0 through 6.2.19

How to fix

Upgrade to a fixed version: Spring Framework 6.2.20, 7.0.8.1. Check the vendor advisory for mitigations.

References

https://spring.io/security/cve-2026-47889

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