OCSP Serial Number Length Confusion in wolfSSL

Mitigation Strategies

To mitigate this vulnerability, update the wolfSSL library to a version that includes the fix for CVE-2026-10098. The fix requires the serial number lengths to be equal before comparing serial bytes in the OCSP response handling function, preventing incorrect revocation status matches.

Specifically, ensure you are using a wolfSSL version released after June 4, 2026, which contains the merged pull request addressing this issue.

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Executive Summary

This vulnerability involves a flaw in the OCSP (Online Certificate Status Protocol) implementation within wolfSSL, specifically in the function wolfSSL_OCSP_resp_find_status. The issue arises because the code compares certificate serial numbers without first checking if their lengths are equal. As a result, a SingleResponse for one certificate whose serial number is a prefix of another certificate's serial number (issued by the same issuer) can be mistakenly matched and reported as the revocation status of the other certificate. This means the system might return the wrong certificate's revocation status.

The fix for this vulnerability requires that the serial numbers must be of equal length before their bytes are compared, preventing incorrect matches.

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Impact Analysis

This vulnerability can lead to incorrect reporting of certificate revocation status. Specifically, a certificate might be incorrectly considered revoked or valid based on the status of a different certificate with a similar serial number prefix. This can undermine the trustworthiness of certificate validation processes, potentially allowing revoked certificates to be accepted or valid certificates to be rejected.

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Compliance Impact

This vulnerability in wolfSSL's OCSP response handling could lead to incorrect certificate revocation status being reported, potentially allowing revoked certificates to be treated as valid.

Such incorrect validation of certificate status may undermine the integrity and trustworthiness of secure communications and identity verification processes.

Since standards and regulations like GDPR and HIPAA require strong security controls to protect data confidentiality and integrity, this vulnerability could negatively impact compliance by weakening certificate validation mechanisms.

However, the provided information does not explicitly state the direct impact on compliance with these regulations.

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