CVE-2026-42771 Details
Description
Issue summary: When the X509_VERIFY_PARAM_set1_email is called by an application to validate a crafted e-mail address, such as during S/MIME message validation, an out of bounds read can happen. Impact summary: This out of bounds read will not directly exfiltrate the data read to the attacker so the most likely result is a crash and a Denial of Service. An internal helper function called from X509_VERIFY_PARAM_[set|add]_email() used a wrong length when validating the local part of an email address. This could cause the 64 octet limit on the local part of an email address to be not enforced, or cause an out of bound read and potentially a crash. The bug is reachable via S-MIME validation with a crafted From: address supplied in an email message that can potentially cause a crash. No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.
A vulnerability exists in OpenSSL 4.0 that allows for an out-of-bounds read when the function X509_VERIFY_PARAM_set1_email is used to validate a crafted email address. This issue can occur during S/MIME message validation, potentially leading to a crash and causing a denial-of-service condition. The vulnerability arises because an internal helper function used in the email validation process applies an incorrect length, which can result in the 64-octet limit on the local part of the email address not being properly enforced. As a consequence, the validation process may either fail to restrict the length appropriately or cause an out-of-bounds read that could be exploited to crash the application.
Users of OpenSSL 4.0 should upgrade to OpenSSL 4.0.1.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 9, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-125 | Out-of-bounds Read | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openssl openssl | 4.0.0 - |
CPE
Remediation
| |
Change History
7 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 16, 2026 | Initial Analysis | [email protected] |
| Jun 10, 2026 | CVE Modified | [email protected] |
| Jun 9, 2026 | CVE Modified | CISA-ADP |
| Jun 9, 2026 | New CVE Received | [email protected] |