CVE-2026-42771
Possible Out of Bounds Read in X509_VERIFY_PARAM_set1_email()
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.
INFO
Published Date :
June 9, 2026, 5:17 p.m.
Last Modified :
June 16, 2026, 2:57 a.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update the OpenSSL library to the latest version.
- Apply vendor patches for affected software.
- Validate email addresses carefully.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42771.
| URL | Resource |
|---|---|
| https://github.com/openssl/openssl/commit/6cd187689f8180c1f8a3acde21f88190c4a20de7 | Patch |
| https://openssl-library.org/news/secadv/20260609.txt | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42771 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42771
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42771 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42771 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 16, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:* Added Reference Type OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/6cd187689f8180c1f8a3acde21f88190c4a20de7 Types: Patch Added Reference Type OpenSSL Software Foundation: https://openssl-library.org/news/secadv/20260609.txt Types: Vendor Advisory -
CVE Modified by [email protected]
Jun. 10, 2026
Action Type Old Value New Value Added Reference https://github.com/openssl/openssl/commit/6cd187689f8180c1f8a3acde21f88190c4a20de7 Removed Reference https://github.com/openssl/security/commit/6cd187689f8180c1f8a3acde21f88190c4a20de7 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 09, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by [email protected]
Jun. 09, 2026
Action Type Old Value New Value Added 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. Added CWE CWE-125 Added Reference https://github.com/openssl/security/commit/6cd187689f8180c1f8a3acde21f88190c4a20de7 Added Reference https://openssl-library.org/news/secadv/20260609.txt