VDB-107903 · CVE-2015-7687 · BID 76975

OpenSMTPD up to 5.7.1 /etc/master.passwd req_ca_vrfy_smtp/req_ca_vrfy_mta use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability, which was classified as critical, has been found in OpenSMTPD up to 5.7.1. This issue affects the function req_ca_vrfy_smtp/req_ca_vrfy_mta of the file /etc/master.passwd. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability.

The bug was discovered 10/02/2015. The weakness was presented 10/16/2017 with Qualys (oss-sec). It is possible to read the advisory at openwall.com. The identification of this vulnerability is CVE-2015-7687 since 10/03/2015. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability was handled as a non-public zero-day exploit for at least 29 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 89451 (Fedora 23 : opensmtpd-5.7.3p1-1.fc23 (2015-ed1c673f09)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context local.

Upgrading to version 5.7.2 eliminates this vulnerability. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (89451).



CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍



VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍


Class: Use after free
CWE: CWE-416 / CWE-119
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Nessus ID: 89451
Nessus Name: Fedora 23 : opensmtpd-5.7.3p1-1.fc23 (2015-ed1c673f09)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍


Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: OpenSMTPD 5.7.2


10/02/2015 🔍
10/02/2015 +0 days 🔍
10/03/2015 +1 days 🔍
10/31/2015 +28 days 🔍
03/04/2016 +125 days 🔍
10/16/2017 +591 days 🔍
10/16/2017 +0 days 🔍
10/17/2017 +1 days 🔍
01/03/2023 +1904 days 🔍


Advisory: FEDORA-2015-ed1c673f09
Researcher: Qualys
Organization: Qualys
Status: Not defined
Confirmation: 🔍

CVE: CVE-2015-7687 (🔍)
SecurityFocus: 76975 - OpenSMTPD CVE-2015-7687 Use After Free Remote Code Execution Vulnerability


Created: 10/17/2017 09:04 AM
Updated: 01/03/2023 05:11 PM
Changes: 10/17/2017 09:04 AM (71), 05/26/2020 08:49 PM (2), 01/17/2021 08:45 AM (2), 01/03/2023 05:11 PM (3)
Complete: 🔍


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