CVE-2026-45185criticalCWE-416

CVE-2026-45185: critical vulnerability in Exim

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48Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 9.8epss 1.3%
from disclosure to weaponsame day
Published on NVDMay 12
1st PoCMay 12
In short

Exim mail server has a use-after-free vulnerability in how it handles chunked email uploads over TLS. When an attacker sends a specially crafted TLS disconnect signal followed by extra data, it corrupts the server's memory and could allow remote code execution without authentication.

Technical detail

CVE-2026-45185 is a use-after-free (CWE-416) in Exim <4.99.3 when using GnuTLS, triggered during BDAT body parsing by sending a TLS close_notify mid-transfer followed by cleartext bytes on the same TCP connection. An unauthenticated remote attacker can achieve heap corruption and arbitrary code execution with a CVSS score of 9.8.

Summary generated and translated by AI from the official description.
Exim before 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path. It is triggered when a client sends a TLS close_notify mid-body during a CHUNKING transfer, followed by a final cleartext byte on the same TCP connection. This can lead to heap corruption. An unauthenticated network attacker exploiting this vulnerability could execute arbitrary code.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Exim · Exim
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