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🛡️ CVE-2026-66140 — exim

🟠 CVSS 8.4 — High ✅ No Known Exploit CWE-24 NVD
8.4
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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 this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs no 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:N/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: None — an unauthenticated stranger can try it.
  • 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

CVE-2026-66140 is classified as CWE-24: Path Traversal: '../filedir'. The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize "../" sequences that can resolve to a location that is outside of that directory.

Affected software

CVE-2026-66140 is recorded against 1 package.

  • exim (fixed in 4.99.5)

Timeline and source

Published on 24 July 2026 and last revised on 17 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

openwall.com

Other advisories for this package

exim 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-24: Path Traversal: '../filedir') in other software:

Details

Severity HIGH
CVSS Score 8.4
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE CWE-24
Public Exploit ✅ No
Source NVD
Published 2026-07-24
Updated 2026-08-20
Modified 2026-08-17
Fix URL N/A

Affected Packages

Software From version Fixed in
exim — 4.99.5

References

Mailing List, Third Party Advisory https://openwall.com/lists/oss-security/2026/07/22/9

Similar Threats

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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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