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🛡️ CVE-2026-66141 on Ubuntu — exim4

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Exim before 4.99.5 allows .forward privilege escalation because force_command for a pipe transport is mishandled.

Distribution advisory

This page covers CVE-2026-66141 as tracked by Ubuntu, for the package exim4. The fix is available in version 4.99.1-1ubuntu1.4; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

UBUNTU-CVE-2026-66141 is classified as CWE-829: Inclusion of Functionality from Untrusted Control Sphere. Code is loaded from a source outside the product's control, so that source can change what runs.

Affected software

UBUNTU-CVE-2026-66141 is recorded against 1 package.

  • exim4 (fixed in 4.99.1-1ubuntu1.4)

Timeline and source

Published on 24 July 2026 and last revised on 19 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
www.openwall.com (Report)
www.exim.org (Report)
openwall.com (Report)
ubuntu.com (Advisory)

Other advisories for this package

exim4 has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-829: Inclusion of Functionality from Untrusted Control Sphere) in other software:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-07-24
Updated 2026-08-20
Modified 2026-08-19
Fix URL N/A

Affected Packages

Software From version Fixed in
exim4 — 4.99.1-1ubuntu1.4

Site Security Check

Is exim4 part of your stack?

UBUNTU-CVE-2026-66141 is rated CVSS 7.4 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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