Exim Buffer Overflow Vulnerability

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

• cpe canonical/ubuntu linux14.04
• cpe canonical/ubuntu linux16.04
• cpe canonical/ubuntu linux17.10
• cpe debian/debian linux7.0
• cpe debian/debian linux8.0
• cpe debian/debian linux9.0
• cpe exim/eximversion unspecified
• vendor Exim Eximversion unspecified

How to fix CVE-2018-6789

• Recommended remediation

  Apply updates per vendor instructions. CISA due date May 3, 2022.

• Official advisories

  • CISA KEV · cisa.gov
  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • NIST NVD · nvd.nist.gov
  • Packet Storm Security · packetstormsecurity.com
  • VulnCheck KEV · vulncheck.com

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. Feb 8, 2018 · Catalog

   Detected

   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.

2. Nov 3, 2021 · CISA KEV

   Known exploited

   Apply updates per vendor instructions.

3. May 3, 2022 · CISA KEV

   Remediation due

   Apply updates per vendor instructions.

4. Jun 16, 2026 · Catalog

   Updated

   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.

Sources

• CISA KEVConfirmed exploitationCVE-2018-6789

  Exim contains a buffer overflow vulnerability in the base64d function part of the SMTP listener that may allow for remote code execution.

  cisa.gov
• CVE.orgVulnerability recordCVE-2018-6789

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2018-6789

  30-day exploitation probability 82.1%

  first.org
• Exploit DatabasePublic exploit reference44571

  Public archive entry. The exploit body is not stored here.

  exploit-db.com
• Exploit DatabasePublic exploit reference45671

  Public archive entry. The exploit body is not stored here.

  exploit-db.com
• NIST NVDVulnerability recordCVE-2018-6789

  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.

  nvd.nist.gov
• Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html

  Packet Storm link already published on the finding.

  packetstormsecurity.com
• VulnCheck KEVConfirmed exploitationCVE-2018-6789

  Exim contains a buffer overflow vulnerability in the base64d function part of the SMTP listener that may allow for remote code execution.

  vulncheck.com

References

• Mailing List · openwall.com
• Exploit · packetstormsecurity.com
• Mailing List · openwall.com
• Broken Link · securityfocus.com
• Broken Link · securitytracker.com
• VulnCheck exploitation evidence · cisa.gov
• Exploit · devco.re
• Vendor Advisory · exim.org
• VulnCheck exploitation evidence · media.defense.gov
• CISA note · nvd.nist.gov
• VulnCheck exploitation evidence · us-cert.cisa.gov
• VulnCheck exploitation evidence · cisa.gov
• VulnCheck exploitation evidence · csk.gov.in
• VulnCheck exploitation evidence · trustwave.com

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.