CVE-2026-45185
Critical
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.
SeverityCritical
CVSS9.8
Exploit probability—
Product
Exim
PublishedMay 12, 2026
First seenMay 12, 2026
Weakness typeCWE-416Use after free
How to fix
Update
- exim exim4.99.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| exim exim | 4.97 ≤ v < 4.99.3 | 4.99.3 |
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