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    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.

    Published:Feb 7, 2018
    Last Modified:Nov 7, 2025
    EPS:Feb 8, 2018
    EPSS Score:0.85059
    CVSS Score:9.8

    CISA Notification

    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.

    Required Action:

    Apply updates per vendor instructions.

    Notes:

    No extra notes provided.

    Due Date
    May 3, 2022
    1592 days ago
    Alert Date
    Nov 3, 2021
    1773 days ago

    Affected Products

    Vendor
    Canonical
    Product
    Ubuntu Linux
    Vendor
    Debian
    Product
    Debian Linux
    Vendor
    Exim
    Product
    Exim

    Exploits

    http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.htmlhttps://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/https://www.exploit-db.com/exploits/44571/https://www.exploit-db.com/exploits/45671/http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.htmlhttps://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/https://www.exploit-db.com/exploits/44571/https://www.exploit-db.com/exploits/45671/https://www.exploit-db.com/exploits/45671https://github.com/beraphin/CVE-2018-6789https://github.com/c0llision/exim-vuln-pochttps://github.com/martinclauss/exim-rce-cve-2018-6789https://github.com/synacktiv/Exim-CVE-2018-6789https://github.com/thistehneisen/CVE-2018-6789-Python3https://www.exploit-db.com/exploits/44571

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    References

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

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High