by Kastro
Paper/Archive/CVE-2026-45185

CVE-2026-45185

Exim Exim — Exim before 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path.

EPSS 1%CVSS 9.8
critical.is priorityof 100
43
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 69.8.698 × 2014.0No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
Exim4.97 – < 4.99.34.99.3CNA

Scores by source

mitre (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refexim.orgrefcode.exim.org/exim/wiki/wiki/EximSecurityrefexim.org/static/doc/security/CVE-2026-45185.txtrefxbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-eximrefnews.ycombinator.com/item?id=48111748refopenwall.com/lists/oss-security/2026/05/12/4refexim.org/static/doc/security/EXIM-Security-2026-05-01.1refopenwall.com/lists/oss-security/2026/05/12/25