Critical Security Update for Postfix: CVE-2026-43964
Summary
RHSA-2026:57174: Red Hat Security Advisory: postfix security update. Affects postfix versions < 2:2.10.1-9.el7_9.1. Fixed in 2:2.10.1-9.el7_9.1. How to fix ↓
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Background
Postfix is a widely used open-source mail transfer agent (MTA) that routes and delivers electronic mail. Known for its performance and security features, Postfix is designed to be a flexible and reliable solution for email handling. However, it has been identified to have a security vulnerability that could potentially allow unauthorized access or denial of service.
Vulnerability Detail
The vulnerability, identified as CVE-2026-43964, originates from a flaw in the Postfix package that could lead to a denial of service condition. This issue arises due to improper handling of certain inputs, which could be exploited by an attacker to crash the mail server or disrupt email services. The CVSS score for this vulnerability is 7.5, indicating a high severity level that necessitates immediate attention.
How To Fix
Minimum fixed version
2:2.10.1-9.el7_9.1
This is the first release that contains the fix.
sudo dnf update postfixTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, users may consider disabling certain features of Postfix that are not critical to their operations until the update can be applied. However, it is strongly recommended to apply the patch as soon as possible to mitigate risks.
Conclusion
The identified vulnerability in Postfix, CVE-2026-43964, poses a significant risk to email services. It is crucial for users to update their Postfix installations to the latest patched version to ensure the security and reliability of their email systems.
See every vulnerability recorded for postfix →
FAQ
CVE-2026-43964 is a security vulnerability in the Postfix mail transfer agent that can lead to denial of service.
The vulnerability has a CVSS score of 7.5, indicating it is of high severity and should be addressed promptly.
You can use the Vulert platform to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected.
If an immediate update is not possible, consider disabling non-essential features of Postfix as a temporary workaround.
More details can be found in the Red Hat Security Advisory and the CVE database.
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