CVEs / CVE-2018-6789
CVE-2018-6789: Exim Buffer Overflow Vulnerability
- Known exploited in the CISA KEV catalog since 3 Nov 2021
- critical 9.8 CVSS 3.1 (NVD)
- EPSS 82.1% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
Are you affected? Check your servers with Stackurity: it lists the software on each server and the vulnerabilities to fix first.
Check your servers with Stackurity Already using Stackurity? Search for CVE-2018-6789
Summary
Exim contains a buffer overflow vulnerability in the base64d function part of the SMTP listener that may allow for remote code execution.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| n/a n/a | n/a | — |
Exploitation
| In CISA KEV since | 3 Nov 2021 |
|---|---|
| Due date for US federal agencies | 3 May 2022 |
| Used in ransomware campaigns | Known |
| Required action | Apply updates per vendor instructions. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-120 |
References
- CVE-2018-6789 on NVD
- CVE-2018-6789 in the CISA KEV catalog
- CVE-2018-6789 on OSV
- http://openwall.com/lists/oss-security/2018/02/10/2 Mailing List, Third Party Advisory
- http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html Exploit, Third Party Advisory, VDB Entry
- http://www.openwall.com/lists/oss-security/2018/02/07/2 Mailing List, Third Party Advisory
- http://www.securityfocus.com/bid/103049 Broken Link, Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040461 Broken Link, Third Party Advisory, VDB Entry
- https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/ Exploit, Third Party Advisory
- https://exim.org/static/doc/security/CVE-2018-6789.txt Vendor Advisory
- https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1 Patch
- https://lists.debian.org/debian-lts-announce/2018/02/msg00009.html Mailing List, Third Party Advisory
- https://usn.ubuntu.com/3565-1/ Third Party Advisory
- https://www.debian.org/security/2018/dsa-4110 Mailing List, Third Party Advisory
- https://www.exploit-db.com/exploits/44571/ Exploit, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/45671/ Exploit, Third Party Advisory, VDB Entry
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6789 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.