CVE-2018-6789An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1.
Updated under an hour ago ()
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It affects exim and 2 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by May 3, 2022, and it is known to be used in ransomware. Treat that date as your deadline.
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Free account, 1 product
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.
- CVSS
- 9.8 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-120
- Known exploited
- Added to CISA KEV Nov 3, 2021; federal remediation due May 3, 2022; known ransomware useApply updates per vendor instructions.
- EPSS (exploitation in the next 30 days)
- 82.14% (percentile 100)
- Assigned by
- mitre
- NVD analysis
- Analyzed
- Record last updated
- Oct 21, 2025
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
exim exim exim:exim | before 4.90.1 | NVD |
debian debian_linux debian:debian_linux | 7.0; 8.0; 9.0 | NVD |
canonical ubuntu_linux canonical:ubuntu_linux | 14.04; 16.04; 17.10 | NVD |
References
- https://exim.org/static/doc/security/CVE-2018-6789.txtx-refsource-confirm, vendor-advisory
- http://www.openwall.com/lists/oss-security/2018/02/07/2mailing-list, x-refsource-mlist, third-party-advisory
- https://usn.ubuntu.com/3565-1/vendor-advisory, x-refsource-ubuntu, third-party-advisory
- http://openwall.com/lists/oss-security/2018/02/10/2x-refsource-confirm, mailing-list, third-party-advisory
- http://www.securitytracker.com/id/1040461vdb-entry, x-refsource-sectrack, broken-link, third-party-advisory
- https://www.debian.org/security/2018/dsa-4110vendor-advisory, x-refsource-debian, mailing-list, third-party-advisory
- https://www.exploit-db.com/exploits/44571/exploit, x-refsource-exploit-db, third-party-advisory, vdb-entry
- https://lists.debian.org/debian-lts-announce/2018/02/msg00009.htmlmailing-list, x-refsource-mlist, third-party-advisory
- https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1x-refsource-confirm, patch
- https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/x-refsource-misc, exploit, third-party-advisory
- http://www.securityfocus.com/bid/103049vdb-entry, x-refsource-bid, broken-link, third-party-advisory
- https://www.exploit-db.com/exploits/45671/exploit, x-refsource-exploit-db, third-party-advisory, vdb-entry
- http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.htmlx-refsource-misc, exploit, third-party-advisory, vdb-entry
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6789us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.