Security readout for executives and security teams
CVE-2018-6789 is a critical remote code execution flaw in Exim mail servers before 4.90.1. An unauthenticated attacker can send a specially crafted SMTP message that may make the server run attacker-controlled code. For executives, exposed mail infrastructure should be treated as urgent because mail servers are commonly internet-facing. Organizations running Exim 4.90 or earlier, especially internet-facing SMTP listeners. Exposure is likely wherever mail gateways, Linux servers, or appliances package Exim and accept unauthenticated SMTP. The bundle does not enumerate all downstream products or CPEs. Treat as immediate remediation for any exposed Exim server. The issue is remotely reachable without authentication, has critical impact, and appears in CISA KEV, making delayed patching a material operational risk. Mitigation focus: Upgrade Exim to 4.90.1 or a vendor-fixed package.; Apply Debian, Ubuntu, or distribution security updates where Exim is packaged.; Inventory all internet-facing SMTP services and confirm the running MTA..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2018-6789 mapping review
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Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://exim.org/static/doc/security/CVE-2018-6789.txtCVE reference · x_refsource_CONFIRM
- USN-3565-1CVE reference · vendor-advisory, x_refsource_UBUNTU
- DSA-4110CVE reference · vendor-advisory, x_refsource_DEBIAN
- 44571CVE reference · exploit, x_refsource_EXPLOIT-DB
- [debian-lts-announce] 20180210 [SECURITY] [DLA 1274-1] exim4 security updateCVE reference · mailing-list, x_refsource_MLIST
- https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1CVE reference · x_refsource_CONFIRM
- https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/CVE reference · x_refsource_MISC
- 45671CVE reference · exploit, x_refsource_EXPLOIT-DB
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6789CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.