CVE-2026-47842 Spring CVE debrief

Who should care

Security teams and developers using Spring Security, particularly those relying on AesBytesEncryptor with CBC mode, should review and update their configurations to mitigate potential security risks. This includes reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Operators, platform administrators, and security teams should be aware of the potential impact and take necessary actions to protect their systems. Vulnerability management and security teams should prioritize this vulnerability and plan for remediation or mitigation as needed. Monitoring and detection teams should also be aware of the potential security issues related to AES/CBC with null IV and review relevant logs for exposed assets that need extra review. Asset inventory management should also be updated to reflect the affected systems and track exceptions and retest remediated assets. The goal is to ensure that all stakeholders are informed and take necessary actions to protect their systems and data. This may involve applying patches or updates for affected Spring Security versions, monitoring for potential security issues, and reviewing compensating controls for exposed systems while remediation is scheduled and verified. By taking these steps, organizations can reduce the risk associated with this vulnerability and protect their systems and data from potential attacks. Security teams should also track the status of remediation efforts and close the item only after evidence is documented. Overall, a coordinated effort is required to address this vulnerability and ensure the security of systems and data. Security teams should also consider implementing additional security measures, such as asset inventory management, to prevent similar vulnerabilities in the future. By prioritizing this vulnerability and taking necessary actions, organizations can minimize the risk associated with CVE-2026-47842 and protect their systems and data from potential security threats. Security teams and developers should work together to ensure that all necessary steps are taken to mitigate the potential security risks associated with this vulnerability. In

Technical summary

The AesBytesEncryptor in Spring Security uses a null (all-zero) initialization vector when configured with a null IV generator and CBC mode. This affects various versions of Spring Security, including 7.1.0, 7.0.0 - 7.0.6, 6.5.0 - 6.5.11, 6.4.0 - 6.4.18, 5.8.0 - 5.8.27, and 5.7.0 - 5.7.25. The vulnerability poses a medium security risk due to the potential impact of using AesBytesEncryptor with a null IV generator and CBC mode.

Defensive priority

Medium-priority defensive actions are recommended due to the potential impact of using AesBytesEncryptor with a null IV generator and CBC mode.

Recommended defensive actions

• Review and update AesBytesEncryptor configurations to use a secure IV generator
• Apply patches or updates for affected Spring Security versions
• Monitor for potential security issues related to AES/CBC with null IV
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record indicates that applications using AesBytesEncryptor with the two-argument constructor or when passing a null IV generator and CBC as the encryption mode encrypt data with AES/CBC using a null (all-zero) initialization vector. Affected versions include Spring Security 7.1.0, 7.0.0 - 7.0.6, 6.5.0 - 6.5.11, 6.4.0 - 6.4.18, 5.8.0 - 5.8.27, and 5.7.0 - 5.7.25.

Sources and 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.