PT-2026-40334 · Gnu+1 · Gnutls+1

Published 2026-05-12 · Updated 2026-05-12 · CVE-2026-45185

Positive Technologies (AI Summary)

CVSS v3.1

9.8

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Exim versions 4.97 through 4.99.2

Description A use-after-free flaw exists in the BDAT (CHUNKING) SMTP extension when Exim is built with GnuTLS. An unauthenticated attacker can trigger this issue by prematurely terminating a TLS session during a binary data transfer, causing the system to write data into a freed memory buffer. This leads to heap corruption, which can be leveraged to achieve remote code execution.

Recommendations Upgrade to version 4.99.3.

Fix

DoS

RCE

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

CVE-2026-45185

Affected Products

Exim

Gnutls

References · 22

• https://nvd.nist.gov/vuln/detail/CVE-2026-45185 · Security Note
• https://news.ycombinator.com/item?id=48111748 · Note
• https://twitter.com/cyberkendra/status/2054248045861355617 · Twitter Post
• https://twitter.com/skywalkerr0x/status/2054259026444394745 · Twitter Post
• https://openwall.com/lists/oss-security/2026/05/12/4 · Note
• https://twitter.com/skywalkerr0x/status/2054259305101341094 · Twitter Post
• https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim · Note
• https://exim.org/static/doc/security/CVE-2026-45185.txt · Note
• https://twitter.com/Xbow/status/2054234664882020377 · Twitter Post
• https://t.me/RNetsec/23115 · Telegram Post
• https://t.me/secharvester/22433 · Telegram Post
• https://exim.org · Note
• https://twitter.com/autumn_good_35/status/2054249791065116963 · Twitter Post
• https://twitter.com/TheHackersNews/status/2054241582099091880 · Twitter Post
• https://t.me/defcon_news/135654 · Telegram Post