Ubuntu 26.04 LTS Exim Critical Remote Code Exec Denial of Service 8834

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Several security issues were fixed in Exim. Software Description: - exim4: Exim is a mail transport agent Details: It was discovered that Exim had an out-of-bounds write when Proxy-Protocol was used with an attacker-controlled proxy. A remote attacker could possibly use this issue to execute arbitrary code. (CVE-2026-94054) It was discovered that Exim had a use-after-free when certain non-default TLS settings were used with GnuTLS. A remote attacker could possibly use this issue to cause Exim to crash, resulting in a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-94055) It was discovered that Exim allowed attackers to read uninitialized data from stack memory when Proxy-Protocol was used with an attacker-controlled proxy. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-94056) It was discovered that Exim allowed SMTP smuggling via crafted data sent after a rejection during DATA processing. A remote attacker co... Read the Full Advisory

Several security issues were fixed in Exim.

Software Description:

- exim4: Exim is a mail transport agent

It was discovered that Exim had an out-of-bounds write when

Proxy-Protocol was used with an attacker-controlled proxy. A remote

attacker could possibly use this issue to execute arbitrary code.

It was discovered that Exim had a use-after-free when certain

non-default TLS settings were used with GnuTLS. A remote attacker

could possibly use this issue to cause Exim to crash, resulting in

a denial of service. This issue only affected Ubuntu 26.04 LTS.

It was discovered that Exim allowed attackers to read uninitialized

data from stack memory when Proxy-Protocol was used with an

attacker-controlled proxy. A remote attacker could possibly use this

issue to obtain sensitive information. (CVE-2026-94056)

It was discovered that Exim allowed SMTP smuggling via crafted data

sent after a rejection during DATA processing. A remote attacker

The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS exim4 4.99.1-1ubuntu1.5 Ubuntu 24.04 LTS exim4 4.97-4ubuntu4.8 Ubuntu 22.04 LTS exim4 4.95-4ubuntu2.12 In general, a standard system update will make all the necessary changes.

CVE-2026-94054, CVE-2026-94055, CVE-2026-94056, CVE-2026-94057

Ubuntu Security Notice USN-8834-1

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