CVE-2026-42771
Published:June 09, 2026
Updated:June 11, 2026
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.
Affected Packages
https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) =openssl-4.0.0 <openssl-4.0.1Fix Suggestion:
Update to version openssl-4.0.1Related Resources (3)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.9
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.2
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Out-of-bounds Read
EPSS
Base Score:
0.01