SB2026060183 - Ubuntu update for exim4

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Main Vulnerability Database SB2026060183

SB2026060183 - Ubuntu update for exim4

Published: June 1, 2026

Security Bulletin ID SB2026060183
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Information disclosure

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Use of Uninitialized Variable (CVE-ID: CVE-2026-48840)

CWE-ID: CWE-457 - Use of Uninitialized Variable

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to an uninitialized stack memory use in the PROXY-protocol parser when parsing a crafted PROXY version 2 frame with an insufficient payload length. A remote attacker can send a specially crafted PROXY frame to disclose sensitive information.

Only builds compiled with SUPPORT_PROXY and configured with a non-empty hosts_proxy are vulnerable. To reach the vulnerable code, the source IP must match hosts_proxy or the crafted PROXY header must be forwarded through a host already listed in hosts_proxy.


Remediation

Install update from vendor's website.

References