---
id: 5166
title: "Dead.Letter (CVE-2026-45185) How XBOW Found an Unauthenticated RCE on Exim"
cve: CVE-2026-45185
cvss: 9.8
severity: critical
source_domain: xbow.com
source_url: "https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim"
published_at: "2026-05-12T14:00:00Z"
tags: ["rce", "vulnerability-research", "use-after-free", "exim", "cve-2026-45185", "gnutls"]
phying_url: "https://phying.com/item/5166"
lang: en
---

# Dead.Letter (CVE-2026-45185) How XBOW Found an Unauthenticated RCE on Exim

## Summary

XBOW recounts finding CVE-2026-45185, an unauthenticated Exim RCE: during GnuTLS TLS shutdown, a nested BDAT wrapper's ungetc() writes one byte into freed memory, corrupting allocator metadata.

## Intelligence Metadata

- **Sources:** xbow.com
- **CVE:** CVE-2026-45185
- **CVSS:** 9.8
- **Published:** 2026-05-12T14:00:00Z
- **Original:** https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim
- **Phying News:** https://phying.com/item/5166