CVE-2026-45185 Details
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.
A use-after-free vulnerability has been identified in Exim versions prior to 4.99.3, specifically in certain GnuTLS configurations. This vulnerability is remotely exploitable and occurs in the BDAT body parsing process. It is triggered when a client sends a TLS close_notify signal mid-transfer during a CHUNKING operation, followed by a cleartext byte on the same TCP connection. This sequence can lead to heap corruption, allowing an unauthenticated network attacker to execute arbitrary code.
Users are advised to upgrade to Exim version 4.99.3 or later.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 13, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| http://www.openwall.com/lists/oss-security/2026/05/12/25 | CVE | Mailing ListThird Party Advisory |
| https://code.exim.org/exim/wiki/wiki/EximSecurity | [email protected] | Vendor Advisory |
| https://exim.org | [email protected] | Product |
| https://exim.org/static/doc/security/CVE-2026-45185.txt | [email protected] | Broken Link |
| https://exim.org/static/doc/security/EXIM-Security-2026-05-01.1/ | [email protected] | Release Notes |
| https://news.ycombinator.com/item?id=48111748 | [email protected] | Issue Tracking |
| https://www.openwall.com/lists/oss-security/2026/05/12/4 | [email protected] | Mailing ListThird Party Advisory |
| https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim | [email protected] | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-416 | Use After Free | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| exim exim | >= 4.97, < 4.99.3 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 28, 2026 | Initial Analysis | [email protected] |
| May 13, 2026 | CVE Modified | CVE |
| May 12, 2026 | CVE Modified | [email protected] |
| May 12, 2026 | New CVE Received | [email protected] |