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Vulnerability record · CVE-2026-45185 · published 12 May 2026

CVE-2026-45185: Exim use after free vulnerability

Exim · Exim

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.

9.8 CVSS 3.1 Critical EPSS 0.94% · top 40.5% CWE-416 · Use after free
9.8CVSS 3.1 base score
0.94%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

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

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://code.exim.org/exim/wiki/wiki/EximSecurity Vendor Advisory
https://exim.org Product
https://exim.org/static/doc/security/CVE-2026-45185.txt Broken Link
https://exim.org/static/doc/security/EXIM-Security-2026-05-01.1/ Release Notes
https://news.ycombinator.com/item?id=48111748 Issue Tracking
https://www.openwall.com/lists/oss-security/2026/05/12/4 Mailing ListThird Party Advisory
https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/05/12/25 Mailing ListThird Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-45185), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.