CVE-2026-66140: Exim before 4.99.5 allows directory traversal to access files outside of the spool area, and consequently gain

Q: How do I fix CVE-2026-66140?

exim: upgrade to 4.99.5. Exact commands for each OS are on this page.

Q: Is CVE-2026-66140 being exploited?

CVE-2026-66140 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-2026-66140 affect?

CVE-2026-66140 affects exim. Severity is high (CVSS 8.4). Exim before 4.99.5 allows directory traversal to access files outside of the spool area, and consequently gain privileges, because arguments related to queue-name are mishandled.

Routine

HIGH 8.4UPGRADE

CVE-2026-66140 is a high-severity flaw (CVSS 8.4) affecting exim. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Exim before 4.99.5 allows directory traversal to access files outside of the spool area, and consequently gain privileges, because arguments related to queue-name are mishandled.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.4 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-24
Published	2026-07-24
Last modified	2026-08-17

Publisher (CNA): MITRE · Vendor: exim

Last updated 2026-08-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-24 05:16 UTCPublished CVE record published
2026-08-17 19:04 UTCUpdated Record last modified

exim exim UPGRADE

Affected: < 4.99.5

Fixed in: 4.99.5

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 4.99.5 (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-2026-66140?

exim: upgrade to 4.99.5. Exact commands for each OS are on this page.

Is CVE-2026-66140 being exploited?

CVE-2026-66140 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-2026-66140 affect?

CVE-2026-66140 affects exim. Severity is high (CVSS 8.4). Exim before 4.99.5 allows directory traversal to access files outside of the spool area, and consequently gain privileges, because arguments related to queue-name are mishandled.

How urgent is CVE-2026-66140?

Priority 38/100. High severity

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
CVE-2026-94057 MEDIUM 4.0 UPGRADE Exim before 4.100.1 allows SMTP smuggling in which the received message does not match any sent message, and i
CVE-2026-66141 HIGH 7.4 UPGRADE Exim before 4.99.5 allows .forward privilege escalation because force_command for a pipe transport is mishandl

References

← Back to latest CVEs