VDB-149181 · CVE-2019-16791 · GHSA-h92m-42h4-82f6

postfix-mta-sts-resolver up to 0.5.0 STS Policy downgrade

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.8	$0-$5k	0.00

Summaryinfo

A vulnerability marked as problematic has been reported in postfix-mta-sts-resolver up to 0.5.0. Affected is an unknown function of the component STS Policy Handler. Performing a manipulation results in downgrade. This vulnerability is identified as CVE-2019-16791. The attack is only possible with local access. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in postfix-mta-sts-resolver up to 0.5.0. It has been classified as problematic. This affects an unknown code of the component STS Policy Handler. The manipulation with an unknown input leads to a downgrade vulnerability. CWE is classifying the issue as CWE-757. A protocol or its implementation supports interaction between multiple actors and allows those actors to negotiate which algorithm should be used as a protection mechanism such as encryption or authentication, but it does not select the strongest algorithm that is available to both parties. This is going to have an impact on confidentiality, and integrity. The summary by CVE is:

In postfix-mta-sts-resolver before 0.5.1, All users can receive incorrect response from daemon under rare conditions, rendering downgrade of effective STS policy.

The weakness was released 01/22/2020 (GitHub Repository). The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2019-16791 since 09/24/2019. The exploitability is told to be difficult. An attack has to be approached locally. The exploitation needs additional levels of successful authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1562.010 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 258014 (Linux Distros Unpatched Vulnerability : CVE-2019-16791), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.5.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (258014). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

postfix-mta-sts-resolver

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.8
VulDB Meta Temp Score: 5.8

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 6.9
NVD Vector: 🔍

CNA Base Score: 6.9
CNA Vector (GitHub, Inc.): 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Downgrade
CWE: CWE-757
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 258014
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2019-16791

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: postfix-mta-sts-resolver 0.5.1

Timelineinfo

09/24/2019 🔍
01/22/2020 +120 days 🔍
01/22/2020 +0 days 🔍
08/28/2025 +2045 days 🔍

Sourcesinfo

Advisory: GHSA-h92m-42h4-82f6
Status: Confirmed

CVE: CVE-2019-16791 (🔍)
GCVE (CVE): GCVE-0-2019-16791
GCVE (VulDB): GCVE-100-149181

Entryinfo

Created: 01/22/2020 10:41
Updated: 08/28/2025 07:53
Changes: 01/22/2020 10:41 (38), 01/22/2020 10:46 (11), 03/25/2024 08:25 (17), 03/25/2024 08:30 (19), 08/28/2025 07:53 (6)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.