CVE-2026-47891: Spring Framework maxInMemorySize Bypassed in Jaxb2Decoder

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-27 · updated 2026-09-02
Weakness: CWE-770

Description

A Spring WebFlux application that relies on the Aalto XML processor to parse XML input does not correctly enforce the maxInMemorySize limit. Spring Framework 7.0.0 - 7.0.8 Spring Framework 6.2.0 - 6.2.19 Spring Framework 6.1.0 - 6.1.28 Spring Framework 6.0.0 - 6.0.30 Spring Framework 5.3.0 - 5.3.49 Spring Framework 5.2.25.RELEASE and earlier

Affected products

Spring Framework: before 5.2.26; from 5.3.0 before 5.3.50; from 6.0.0 before 6.0.31; from 6.1.0 before 6.1.29; from 6.2.0 before 6.2.20; from 7.0.0 before 7.0.8.1 — fixed in 5.2.26, 5.3.50, 6.0.31, 6.1.29, 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; from 6.1.0 through 6.1.28; from 6.0.0 through 6.0.30; from 5.3.0 through 5.3.49; through 5.2.25.RELEASE

How to fix

Upgrade to a fixed version: Spring Framework 5.2.26, 5.3.50, 6.0.31, 6.1.29. Check the vendor advisory for mitigations.

References

https://spring.io/security/cve-2026-47891

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