OpenSSL X.509 Email Validation Out-Of-Bounds Read Information Disclosure Vulnerability

July 15th, 2026
ZDI-26-426 ZDI-CAN-30378

CVE ID

CVE-2026-42771

CVSS Score

6.5 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

Affected Vendors

OpenSSL

Affected Products

OpenSSL

Vulnerability Details

This vulnerability allows remote attackers to disclose sensitive information on affected installations of OpenSSL. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the processing of expected X.509 email names. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated buffer. An attacker can leverage this vulnerability to disclose information in the context of the service account.

Additional Details

OpenSSL has issued an update to correct this vulnerability. More details can be found at:
https://openssl-library.org/news/vulnerabilities/#CVE-2026-42771

Disclosure Timeline

  • 2026-04-16 - Vulnerability reported to vendor
  • 2026-07-15 - Coordinated public release of advisory
  • 2026-07-15 - Advisory Updated

Credit

TrendAI Zero Day Initiative

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