Review reviewHigh

CVE-2026-40988

Spring Spring Security, spring security

An application using spring-security-saml2-service-provider and the REDIRECT binding for SAML 2.0 Login or Logout may be vulnerable to a denial of service by way of an unbounded writer that inflates the compressed SAML payload into memory. Affected versions: Spring Security 5.7.0 through 5.7.23; 5.8.0 through 5.8.25; 6.3.0 through 6.3.16; 6.4.0 through 6.4.16; 6.5.0 through 6.5.10; 7.0.0 through 7.0.5.

CVSS: 7.5
EPSS: 0.33%
CISA KEV: Not listed
Published: 2026.06.10

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.33%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: Spring Spring Security, spring security
Affected versions: >= 5.7.0 < 5.7.24, >= 5.8.0 < 5.8.26, >= 6.3.0 < 6.3.17, >= 6.4.0 < 6.4.17, >= 6.5.0 < 6.5.10.2, >= 7.0.0 < 7.0.5.1
Fixed versions: 5.7.24, 5.8.26, 6.3.17, 6.4.17, 6.5.10.2, 7.0.5.1

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Spring Spring Security, spring security and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-400