# CVE-2018-6789

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.

- Page: https://www.vulneraibility.com/cve/CVE-2018-6789
- CVSS: 9.8
- Known exploited: yes, in CISA KEV since 2021-11-03; CISA due date 2022-05-03; known ransomware use
- EPSS: 82.14% (percentile 99.7)
- Public exploit code: 2 on Exploit-DB · 5 GitHub proofs of concept (first 2018-03-16)
- CISA SSVC: exploitation active, automatable yes, technical impact total (assessed 2025-02-07)
- Weakness: CWE-120
- Published: 2018-02-08

## Affected

- exim:exim
- debian:debian_linux
- canonical:ubuntu_linux

## References

- [other] https://exim.org/static/doc/security/CVE-2018-6789.txt
- [other] http://www.openwall.com/lists/oss-security/2018/02/07/2
- [advisory] https://usn.ubuntu.com/3565-1/
- [other] http://openwall.com/lists/oss-security/2018/02/10/2
- [other] http://www.securitytracker.com/id/1040461
- [advisory] https://www.debian.org/security/2018/dsa-4110
- [exploit] https://www.exploit-db.com/exploits/44571/
- [other] https://lists.debian.org/debian-lts-announce/2018/02/msg00009.html
- [other] https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1
- [other] https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/
- [other] http://www.securityfocus.com/bid/103049
- [exploit] https://www.exploit-db.com/exploits/45671/
- [other] http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6789

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.