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PatchSiren cyber security CVE debrief

CVE-2026-41839 Spring CVE debrief

A WebFlux application with a compromised subdomain (for example, compromised via cross-site scripting (XSS)) is vulnerable to an escalation attack exchanging a known session ID for that of an authenticated user. This vulnerability affects Spring Framework versions 7.0.0 through 7.0.7, 6.2.0 through 6.2.18, 6.1.0 through 6.1.27, and 5.3.0 through 5.3.48.

Vendor
Spring
Product
Spring Framework
CVSS
MEDIUM 4.2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-07-14
Advisory published
2026-06-09
Advisory updated
2026-07-14

Who should care

Users of Spring Framework versions 7.0.0 through 7.0.7, 6.2.0 through 6.2.18, 6.1.0 through 6.1.27, and 5.3.0 through 5.3.48 who utilize WebFlux applications.

Technical summary

The vulnerability allows an attacker to exchange a known session ID for that of an authenticated user in a WebFlux application, potentially leading to unauthorized access. The CVSS score for this vulnerability is 4.2, indicating a medium severity.

Defensive priority

Medium

Recommended defensive actions

  • Update to a non-vulnerable version of Spring Framework.
  • Implement additional security measures to prevent subdomain compromise, such as monitoring for suspicious activity and enforcing secure coding practices.

Evidence notes

The CVE record and NVD detail provide further information on this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-41839 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-41839

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-41839 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-41839

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.