HIGH
CVE-2003-0743
NVD-CWE-OtherPublished: October 20, 2003· Updated: Jun 16, 2026
7.5
CVSS v3.1
Official Description
Heap-based buffer overflow in smtp_in.c for Exim 3 (exim3) before 3.36 and Exim 4 (exim4) before 4.21 may allow remote attackers to execute arbitrary code via an invalid (1) HELO or (2) EHLO argument with a large number of spaces followed by a NULL character and a newline, which is not properly trimmed before the "(no argument given)" string is appended to the buffer.
Technical Analysis
CVE-2003-0743 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.
User Interaction
Scope
Impact
ConfidentialityP
IntegrityP
AvailabilityP
AV:N/AC:L/Au:N/C:P/I:P/A:P
Affected Vendors & Products
university_of_cambridge1 product(s)
exim
Source: NVD CPE · 25 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (18)
→
http://www.debian.org/security/2003/dsa-376Patch · Vendor Advisory
→
http://www.debian.org/security/2003/dsa-376Patch · Vendor Advisory
Quick Facts
CVE IDCVE-2003-0743
CVSS Score7.5 / 10
SeverityHIGH
WeaknessNVD-CWE-Other
CISA KEVNo
Affected1 vendor(s)
PublishedOct 20, 2003
Related CVEs (NVD-CWE-Other)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2003-0743 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.