CVE-2003-0743

CVE-2003-0743 is a high-severity vulnerability in University Of Cambridge Exim with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

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.

Frequently asked questions

What is CVE-2003-0743?
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.
How severe is CVE-2003-0743?
CVE-2003-0743 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2003-0743 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2003-0743?
CVE-2003-0743 primarily affects University Of Cambridge Exim. In total, 25 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2003-0743?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2003-0743 published?
CVE-2003-0743 was published on 2003-10-20 and last updated on 2026-06-16.

References

Affected products (25)

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