Vulnerability Report

CVE-2026-45185

Title: Use-after-free in Exim GnuTLS BDAT parsing

Memory Corruption

Proof Of Concept

PoC Available for CVE-2026-45185

CWE Category NVD-CWE-noinfo

Published Date May 12, 2026

Modified Date May 28, 2026

Exploit Status Available

Score 9.8 CVSS v

Exploit Probability (EPSS)

1.22%

Vulnerability Summary

CVE-2026-45185: 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.

Impacted Vendors

university_of_cambridge 1

exim 1

Reference Links

https://code.exim.org/exim/wiki/wiki/EximSecurity https://exim.org https://exim.org/static/doc/security/CVE-2026-45185.txt https://exim.org/static/doc/security/EXIM-Security-2026-05-01.1/ https://news.ycombinator.com/item?id=48111748 https://www.openwall.com/lists/oss-security/2026/05/12/4 https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim

CVSS v3.1

Source Entity [email protected]

Severity CRITICAL

9.8

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-45185 Exploits & PoCs (Proof Of Concept)

GitHub https://github.com/liamromanis101/Dead.Letter-CVE-2026-45185

View Code

GitHub https://github.com/materaj2/cve-2026-45185-detection-script

View Code

GitHub https://github.com/MJ-bin/POC_CVE-2026-45185

View Code

May 28, 2026 MODIFIED

Vulnerability data updated via NVD.

May 13, 2026 MODIFIED

Vulnerability data updated via NVD.

May 12, 2026 MODIFIED

Vulnerability data updated via NVD.

May 12, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Stack

No specific products linked.