Description
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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | exim4 | 4.90.1-1 | — |
| Debian 13 | exim4 | 4.90.1-1 | — |
| Debian 12 | exim4 | 4.90.1-1 | — |
| Debian 9 | exim4 | 4.89-2+deb9u3 | DSA-4110-1 |
| Debian 8 | exim4 | 4.84.2-2+deb8u5 | DSA-4110-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 7 | exim4 | 4.80-7+deb7u6 | DLA-1274-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | exim4 | 4.86.2-2ubuntu2.3 | USN-3565-1 |
| Ubuntu 14.04 LTS | exim4 | 4.82-3ubuntu2.4 | USN-3565-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP2 | exim | 4.94.2-bp152.6.4.1 | openSUSE-SU-2021:0754-1 |
| SUSE Package Hub 15 SP2 | libspf2 | 1.2.10-bp152.5.1 | openSUSE-SU-2021:0754-1 |
| SUSE Package Hub 15 SP1 | exim | 4.94.2-bp151.2.4.1 | openSUSE-SU-2021:0753-1 |
| SUSE Package Hub 15 SP1 | libspf2 | 1.2.10-bp151.4.1 | openSUSE-SU-2021:0753-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | exim | 4.94.2-4.2 | openSUSE-SU-2024:10746-1 |
| openSUSE Leap 15.2 | exim | 4.94.2-lp152.8.3.1 | openSUSE-SU-2021:0677-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | exim | 4.90.1-r0 | — |
| Alpine v3.23 | exim | 4.90.1-r0 | — |
| Alpine v3.22 | exim | 4.90.1-r0 | — |
| Alpine v3.21 | exim | 4.90.1-r0 | — |
| Alpine v3.20 | exim | 4.90.1-r0 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | exim | 4.90.1-r0 | — |
| Alpine v3.18 | exim | 4.90.1-r0 | — |
| Alpine v3.17 | exim | 4.90.1-r0 | — |
| Alpine v3.16 | exim | 4.90.1-r0 | — |
| Alpine v3.15 | exim | 4.90.1-r0 | — |
| Alpine v3.14 | exim | 4.90.1-r0 | — |
| Alpine v3.13 | exim | 4.90.1-r0 | — |
| Alpine v3.12 | exim | 4.90.1-r0 | — |
| Alpine v3.11 | exim | 4.90.1-r0 | — |
| Alpine v3.10 | exim | 4.90.1-r0 | — |
| Alpine v3.9 | exim | 4.90.1-r0 | — |
| Alpine v3.8 | exim | 4.90.1-r0 | — |
| Alpine v3.7 | exim | 4.90.1-r0 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 2
- exim 4.90 - Remote Code Execution EDB-45671 · remote · Oct 24, 2018
- Exim < 4.90.1 - 'base64d' Remote Code Execution EDB-44571 · remote · May 2, 2018
GitHub 5 repositories
-
martinclauss/exim-rce-cve-2018-6789 ★ 11 · Mar 2, 2020
This repository provides a learning environment to understand how an Exim RCE exploit for CVE-2018-6789 works.
-
synacktiv/Exim-CVE-2018-6789 ★ 10 · Oct 10, 2019
PoC materials to exploit CVE-2018-6789
-
beraphin/CVE-2018-6789 ★ 3 · Nov 8, 2018
-
thistehneisen/CVE-2018-6789-Python3 ★ 2 · Aug 5, 2023
Exim < 4.90.1 RCE Vulnerability remake for Python3 with arguments passed from CLI
-
c0llision/exim-vuln-poc ★ 0 · Mar 16, 2018
CVE-2018-6789
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 7
- USN-3565-1 exim4 vulnerability Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4110-1 exim4 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1274-1 exim4 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2021:0754-1 Security update for exim SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10746-1 exim-4.94.2-4.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0677-1 Security update for exim SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0753-1 Security update for exim SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://exim.org/static/doc/security/CVE-2018-6789.txt
- [oss-security] 20180207 CVE-2018-6789 Exim 4.90 and earlier: buffer overflow mailing-list
- USN-3565-1 vendor-advisory
- http://openwall.com/lists/oss-security/2018/02/10/2
- 1040461 vdb-entry
- DSA-4110 vendor-advisory
- 44571 exploit
- [debian-lts-announce] 20180210 [SECURITY] [DLA 1274-1] exim4 security update mailing-list
- 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/
- 103049 vdb-entry
- 45671 exploit
- http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html