📄 Exim 4.91 Remote Command Execution

Exim versions 4.87 through 4.91 improper recipient-address validation remote command execution exploit. Spawns a netcat shell on port 31415 as root, then connects to it Vulnerablity is within Exim 4.87-4.91 import subprocess import socket import os import time from subprocess import Popen, PIPE...

CLSA-2026-1778173472 exim: Fix of 2 CVEs

CVE-2026-40685: fix heap corruption when expanding malformed JSON - CVE-2026-40687: fix heap buffer overflow and infoleak in SPA authenticator...

Exploit for OS Command Injection in Exim

No d...

CLSA-2026-1778024757 exim: Fix of CVE-2026-40687

CVE-2026-40687: fix uninitialized buffer and out-of-bounds writes in SPA authenticator...

exim: Fix of CVE-2026-40687

CVE-2026-40687: fix uninitialized buffer and out-of-bounds writes in SPA authenticator...

CVE-2026-40685

A flaw was found in Exim. When JSON lookup is enabled, a remote attacker can send specially crafted malformed JSON in an untrusted header, leading to an out-of-bounds heap write. This issue, caused by an incorrect implementation of backslash skipping, can result in a denial of service...

CVE-2026-40687

A flaw was found in Exim. When the Secure Password Authentication SPA driver processes input from a malicious SPA resource, it can lead to an out-of-bounds write, causing the connection to crash and resulting in a Denial of Service DoS. This vulnerability also allows for the disclosure of sensiti...

CVE-2026-40684

A flaw was found in Exim, specifically on systems utilizing musl libc. A remote attacker can exploit this vulnerability by providing malformed DNS data within PTR records. This can lead to the mail transfer agent MTA connection instance crashing, resulting in a Denial of Service DoS for affected...

Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : Exim vulnerabilities (USN-8228-1)

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8228-1 advisory. It was discovered that Exim incorrectly handled parsing malformed JSON in message headers. A remote attacker could possib...

USN-8228-1: Exim vulnerabilities

It was discovered that Exim incorrectly handled parsing malformed JSON in message headers. A remote attacker could possibly use this issue to execute arbitrary code. CVE-2026-40685 It was discovered that Exim incorrectly handled processing of UTF-8 trailing characters. A remote attacker could...

USN-8228-1 exim4 vulnerabilities

It was discovered that Exim incorrectly handled parsing malformed JSON in message headers. A remote attacker could possibly use this issue to execute arbitrary code. CVE-2026-40685 It was discovered that Exim incorrectly handled processing of UTF-8 trailing characters. A remote attacker could...

CVE-2026-40686

A flaw was found in Exim when UTF-8 operators are enabled. A remote attacker could exploit this by sending malformed UTF-8 header data with large trailing characters, leading to an out-of-bounds read. This vulnerability may result in information disclosure within an error message, potentially...

CVE-2026-40684

In Exim before 4.99.2, on systems using musl libc not glibc, an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dnexpand oddity in octal printing...

CVE-2026-40686

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present malformed UTF-8 header data. Information might be divulged within an error message produced during handling of an unrelated e-mail message...

CVE-2026-40687

In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory...

CVE-2026-40685

In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping...

EUVD-2026-26444

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present malformed UTF-8 header data. Information might be divulged within an error message produced during handling of an unrelated e-mail message...

CVE-2026-40685

In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping...

EUVD-2026-26445

In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory...

CVE-2026-40687

In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory...