How severe is CVE-2003-0540?

CVE-2003-0540 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2003-0540 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 21% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2003-0540?

CVE-2003-0540 primarily affects Wietse Venema Postfix. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2003-0540?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2003-0540 published?

CVE-2003-0540 was published on 2003-08-27 and last updated on 2026-06-16.

CVE-2003-0540

CVE-2003-0540 is a medium-severity vulnerability in Wietse Venema Postfix with a CVSS 2.0 base score of 5.0. Its EPSS exploit-prediction score of 21% places it in the 97th percentile, indicating an elevated likelihood of exploitation.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 21% (97th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Wietse Venema Postfix
Published: 2003-08-27
Last modified: 2026-06-16

Description

The address parser code in Postfix 1.1.12 and earlier allows remote attackers to cause a denial of service (lock) via (1) a malformed envelope address to a local host that would generate a bounce and contains the ".!" string in the MAIL FROM or Errors-To headers, which causes nqmgr to lock up, or (2) via a valid MAIL FROM with a RCPT TO containing a ".!" string, which causes an instance of the SMTP listener to lock up.

Frequently asked questions

What is CVE-2003-0540?: The address parser code in Postfix 1.1.12 and earlier allows remote attackers to cause a denial of service (lock) via (1) a malformed envelope address to a local host that would generate a bounce and contains the ".!" string in the MAIL FROM or Errors-To headers, which causes nqmgr to lock up, or (2) via a valid MAIL FROM with a RCPT TO containing a ".!" string, which causes an instance of the SMTP listener to lock up.
How severe is CVE-2003-0540?: CVE-2003-0540 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2003-0540 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 21% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2003-0540?: CVE-2003-0540 primarily affects Wietse Venema Postfix. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2003-0540?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2003-0540 published?: CVE-2003-0540 was published on 2003-08-27 and last updated on 2026-06-16.

References

Affected products (9)

cpe:2.3:a:wietse_venema:postfix:1.0.21:*:*:*:*:*:*:*
cpe:2.3:a:wietse_venema:postfix:1.1.11:*:*:*:*:*:*:*
cpe:2.3:a:wietse_venema:postfix:1.1.12:*:*:*:*:*:*:*
cpe:2.3:a:wietse_venema:postfix:1999-09-06:*:*:*:*:*:*:*
cpe:2.3:a:wietse_venema:postfix:1999-12-31:*:*:*:*:*:*:*
cpe:2.3:a:wietse_venema:postfix:2000-02-28:*:*:*:*:*:*:*
cpe:2.3:a:wietse_venema:postfix:2001-11-15:*:*:*:*:*:*:*
cpe:2.3:o:conectiva:linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:conectiva:linux:8.0:*:*:*:*:*:*:*