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Fencer Vulns
critical 9.8

CVE-2026-45185 json

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

published 2026-05-12 5 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-29824

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

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.

Patch / fix

  • Exim Exim 4.99.3
  • exim4 Debian 12 4.96-15+deb12u9
  • exim4 Debian 13 4.98.2-1+deb13u2
  • exim4 Debian 14 4.99.2-2

debian advisories DEBIAN-CVE-2026-45185

  • exim4 Ubuntu 22.04 LTS 4.95-4ubuntu2.8
  • exim4 Ubuntu 24.04 LTS 4.97-4ubuntu4.5
  • exim4 Ubuntu 25.10 4.98.2-1ubuntu2.2
  • exim4 Ubuntu 26.04 LTS 4.99.1-1ubuntu1.2
  • exim4 Ubuntu Pro 20.04 LTS 4.93-13ubuntu1.12+esm1

ubuntu advisories UBUNTU-CVE-2026-45185

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-45185 updated cvss 9.8

exim: Exim: Arbitrary code execution via use-after-free in BDAT body parsing.

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
5 mo ago

Exploit prediction

1.27% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Exim Exim

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.