CVE-2018-6789

Exim: Buffer Overflow

As of , CVE-2018-6789 in Exim is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 3 November 2021
US federal deadline
3 May 2022181 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Known
EPSS score
0.82Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
Not availableCISA listed it before 4 February 2022, where the EPSS files we read begin.
Public exploit
2 Exploit-DB entries
Fix
No vendor link in CISA's entry

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

Exim contains a buffer overflow vulnerability in the base64d function part of the SMTP listener that may allow for remote code execution.

CISA's 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.

The CVE record's description, from mitre

CVE published
8 February 2018
Assigned by
mitre
CVSS
9.8 Critical (CVSS 3.1, from CISA-ADP)
CWE-120
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-119
Improper Restriction of Operations within the Bounds of a Memory Buffer
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. Exploit-DB published an exploit (EDB-ID 44571).
  3. Exploit-DB published an exploit (EDB-ID 45671).
  4. CISA added it to its list of exploited vulnerabilities.
  5. The US federal deadline to fix it.

Public exploits

Facts from Metasploit's module list and Exploit-DB's index; we never copy exploit code.

Exim: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2010-4344Heap-Based Buffer OverflowExim EximPatch this weekMetasploit module; EPSS 0.72; verified Exploit-DB entry0.72
CVE-2010-4345Privilege EscalationExim EximPatch this weekMetasploit module; verified Exploit-DB entry0.18

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