CVE-2018-6789
CRITICAL severity · CVSS 9.8 · Buffer overflow · actively exploited (CISA KEV)
9.8CVSS CRITICAL ● exploited ⚠ ransomware
🔴 Actively exploited in the wild (CISA Known Exploited Vulnerabilities).
⚠ Known use in ransomware campaigns. Added to KEV 2021-11-03. US federal agencies must patch by 2022-05-03.
Summary
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.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)87%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products we track (1)
Recommendation
This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.
Official patch: https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1 ↗
Additional information
- NVD record
- https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1Patch
- https://exim.org/static/doc/security/CVE-2018-6789.txtAdvisory
- http://openwall.com/lists/oss-security/2018/02/10/2Advisory
- http://www.openwall.com/lists/oss-security/2018/02/07/2Advisory
- http://www.securityfocus.com/bid/103049Advisory
- http://www.securitytracker.com/id/1040461Advisory
- http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.htmlAdvisory
- https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/Advisory