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CVE-2018-6789

Exim — Exim Buffer Overflow Vulnerability

Exim · CWE-120 — Classic buffer overflow · in CISA KEV since 2021-11-03

ExigentKEV since 2021 · listed over a yearRansomwareCISA KEVActively Exploited
89

EVRS 89 of 100 Immediate

Out-of-Band / Urgent Remediation

Rank 164 of 2,960 tracked

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Why it scores 89

Evidence available: 6 of 7 signals

Listed in the CISA KEV catalog, and associated with known ransomware campaigns.

  • CISA KEVApplied
  • RansomwareApplied
  • Vendor exploitationDid not apply
  • EPSSApplied
  • Microsoft Exploitability IndexNot applicable
  • Pre-patch disclosureNo data
  • KEV recencyDid not apply
  • CVSSApplied

The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data

Fix

Patch or fixed version identified

CISA required action

Fixed in

exim4 -> 4.82-3ubuntu2.4 | exim4 -> 4.86.2-2ubuntu2.3 | exim4 -> 4.90.1-1

Affected versions

  • exim< 4.90.1
  • debian linux7.08.09.0
  • ubuntu linux14.0416.0417.10

Remediation

Apply updates per vendor instructions.

Fixed versions from NVD.

Evidence

Each value with its source
MeasureValueSource
CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. 9.8 NVD
FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. 0.821 (99.66th pctl) FIRST EPSS
Actively exploitedWhether a source of record has confirmed attacks using it in the wild. Confirmed CISA KEV
Ransomware campaign useWhether CISA has seen ransomware operators use it. Known CISA KEV
CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. 2022-05-03 · KEV since 2021 · listed over a year CISA KEV
Public exploit moduleA module existing is not the same as active exploitation. None known Metasploit
EUVD cross-referenceENISA's record: CVSS 9.8 (v3.1), assigned by mitre. Listed ENISA EUVD

Description

NVD

An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.

What CISA says to do