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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.

PUBLISHED Reserved 2026-05-10 | Published 2026-05-12 | Updated 2026-05-14 | Assigner mitre




CRITICAL: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Problem types

CWE-416 Use After Free

Product status

Default status
unaffected

4.97 (custom) before 4.99.3
affected

References

www.openwall.com/lists/oss-security/2026/05/12/25

exim.org

code.exim.org/exim/wiki/wiki/EximSecurity

exim.org/static/doc/security/CVE-2026-45185.txt

xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim

news.ycombinator.com/item?id=48111748

www.openwall.com/lists/oss-security/2026/05/12/4

exim.org/static/doc/security/EXIM-Security-2026-05-01.1/

cve.org (CVE-2026-45185)

nvd.nist.gov (CVE-2026-45185)

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