CVE-2026-94057: Exim before 4.100.1 allows SMTP smuggling in which the received message does not match any sent message, and i

Q: How do I fix CVE-2026-94057?

exim: upgrade to 4.100.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-94057 being exploited?

CVE-2026-94057 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-94057 affect?

CVE-2026-94057 affects exim. Severity is medium (CVSS 4.0). Exim before 4.100.1 allows SMTP smuggling in which the received message does not match any sent message, and instead depends on crafted data sent after a rejection during DATA processing.

Q: How urgent is CVE-2026-94057?

Priority 21/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 4.0REMOTEUPGRADE

CVE-2026-94057 is a medium-severity flaw (CVSS 4.0) affecting exim. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Exim before 4.100.1 allows SMTP smuggling in which the received message does not match any sent message, and instead depends on crafted data sent after a rejection during DATA processing.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	4.0 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 91%)
CISA exploited list	No
Weakness	CWE-93
Published	2026-09-19
Last modified	2026-09-24

Publisher (CNA): MITRE · Vendor: exim

Last updated 2026-09-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-19 23:17 UTCPublished CVE record published
2026-09-24 20:40 UTCUpdated Record last modified

exim exim UPGRADE

Affected: < 4.100.1

Fixed in: 4.100.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy exim || rpm -q exim || exim --version

2. UPGRADE to 4.100.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade exim

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade exim

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-94057?

exim: upgrade to 4.100.1. Exact commands for each OS are on this page.

Is CVE-2026-94057 being exploited?

CVE-2026-94057 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-94057 affect?

CVE-2026-94057 affects exim. Severity is medium (CVSS 4.0). Exim before 4.100.1 allows SMTP smuggling in which the received message does not match any sent message, and instead depends on crafted data sent after a rejection during DATA processing.

How urgent is CVE-2026-94057?

Priority 21/100. Remotely exploitable, no login, no user action

Software pages

Exim vulnerabilities

Related CVEs

CVE-2026-94054 HIGH 7.0 UPGRADE Exim before 4.100.1, when Proxy-Protocol is used with an attacker-controlled proxy, has an out-of-bounds write
CVE-2026-94055 LOW 3.7 UPGRADE Exim before 4.100.1, when certain non-default TLS settings are used with GnuTLS, has a use-after-free.
CVE-2026-94056 HIGH 7.5 UPGRADE Exim before 4.100.1, when Proxy-Protocol is used with an attacker-controlled proxy, allows attackers to read c

References

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