Exim · Exim
CVE-2018-6789
Exim Buffer Overflow Vulnerability
Exploited in attacks
Used by ransomware
Critical 9.8 Attack chance: 82%
What it is
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.
CISA: Exim contains a buffer overflow vulnerability in the base64d function part of the SMTP listener that may allow for remote code execution.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: May 3, 2022
- Added to the CISA list
- November 3, 2021
- Published
- February 8, 2018
- Severity
- Critical 9.8 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 82% in the top 0.3% of all known vulnerabilities
- Weakness
- CWE-119
- More details
- NVD · CVE.org · CISA
All references (13)
- https://usn.ubuntu.com/3565-1/
- https://www.debian.org/security/2018/dsa-4110
- https://exim.org/static/doc/security/CVE-2018-6789.txt
- http://www.openwall.com/lists/oss-security/2018/02/07/2
- http://openwall.com/lists/oss-security/2018/02/10/2
- http://www.securitytracker.com/id/1040461
- https://www.exploit-db.com/exploits/44571/
- https://lists.debian.org/debian-lts-announce/2018/02/msg00009.html
- https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1
- https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/
- http://www.securityfocus.com/bid/103049
- https://www.exploit-db.com/exploits/45671/
- http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html
More exploited flaws from Exim
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Mar 25, 2022 | Heap-Based Buffer Overflow | Exim | Critical 9.8 | 72% |
| Mar 25, 2022 | Privilege Escalation | Exim | High 7.8 | 18% |
| Mar 3, 2022 | Out-of-bounds Write | Exim Internet Mailer | Critical 9.8 | 42% |
| Jan 10, 2022 | Improper Input Validation | Mail Transfer Agent (MTA) | Critical 9.0 | >99.9% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.