Postfix Denial of Service Vulnerability in Ubuntu Releases

Linuxsecurity

Postfix Denial of Service Vulnerability in Ubuntu Releases

First seen 7 May 2026, 21:08 UTC • •45.9

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ThreatCluster •May 8, 2026 at 21:05 UTC

•Postfix vulnerability allows denial of service via crafted network traffic.
•Affected Ubuntu versions include 26.04 LTS, 25.10, 24.04 LTS, and 22.04 LTS.
•Users should update to the latest Postfix package versions to mitigate risks.

A denial of service vulnerability has been identified in Postfix, affecting multiple Ubuntu releases including 26.04 LTS, 25.10, 24.04 LTS, and 22.04 LTS. Discovered by Kamil Frankowicz, the flaw allows remote attackers to crash Postfix by sending specially crafted network traffic. The vulnerability is tracked as CVE-2026-43964, which was published on May 4, 2026. Users are advised to update their systems to the latest package versions to mitigate the risk. The affected versions include Postfix 3.10.6-4ubuntu2.1 for Ubuntu 26.04 LTS and earlier versions for other releases. A standard system update is recommended to address this issue. The vulnerability does not appear to be actively exploited at this time.

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Timeline

2026-05-04

CVE-2026-43964 published

A denial of service vulnerability in Postfix was officially published, detailing the flaw's potential impact.

2026-05-07

Vulnerability disclosed

Kamil Frankowicz disclosed that Postfix incorrectly handled enhanced status codes, allowing crashes.

2026-05-07

Patch recommendation issued

Users are urged to update to the latest Postfix versions to prevent potential denial of service attacks.

More articles in this cluster (3)

Threat Graph

6 entities, 5 inferred relationships (STIX 2.1).

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Technique (2)

DDoS
Denial of Service

Organization (1)

Ubuntu

Vulnerability (1)

CVE-2026-43964

Weakness (1)

Cwe-400 - Uncontrolled Resource Consumption

Affected Platform (1)

Postfix

Relationships

CVE-2026-43964 targets Postfix
DDoS targets Postfix
Denial of Service targets Postfix
CVE-2026-43964 related to Ubuntu
CVE-2026-43964 related to Cwe-400 - Uncontrolled Resource Consumption

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