What’s Vulnerable › Vulnerabilities

CVE-2026-45185

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-12 · updated 2026-06-17
• Weakness: CWE-416

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.

Affected products

• Exim: from 4.97 before 4.99.3 — fixed in 4.99.3

How to fix

Upgrade to a fixed version: Exim 4.99.3. Check the vendor advisory for mitigations.

References

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

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