CVE-2003-0540Postfix Vulnerability
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…
Published Aug 27, 2003 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2003-0540
Key Facts
Routine patching- CVE-2003-0540 is a medium-severity vulnerability (CVSS 5.0 v2) affecting Postfix (Wietse Venema), Linux (Conectiva).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 21% probability of exploitation in the next 30 days.
- Fixed versions are available, including Postfix 1.1.11-0.woody3, Postfix 1.1.12.
- Brandefense priority: routine patching, as no exploitation is known and its severity is moderate or low.
Scores
CVSS v2
5.0
AV:N/AC:L/Au:N/C:N/I:N/A:P
EPSS (30-day exploit likelihood)
21%
Higher than 97.5% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
34/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
2
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2003-0540
- advisoryRHSA-2003:251
- patchDSA-363
- patchRHSA-2003:251
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.
Affected Products
20 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| PostfixWietse Venema | 1.0.21, 1.1.11, 1.1.12, 1999-09-06, 1999-12-31, 2000-02-28, 2001-11-15 | 1.1.12 |
| LinuxConectiva | 7.0, 8.0 | n/a |
Patched Releases
Postfix
1.1.11-0.woody3, 1.1.12
Timeline
Publicly disclosed
Aug 27, 2003
Last updated
Aug 4, 2026
References
- advisorysecurity-tracker.debian.org · CVE-2003-0540
- advisoryRHSA-2003:251
- patchDSA-363
- patchRHSA-2003:251
- exploitExploitDB-22981
FAQ
Common Questions.
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…
Affected: Postfix (Wietse Venema) versions 1.0.21, 1.1.11, 1.1.12, 1999-09-06, 1999-12-31, 2000-02-28, 2001-11-15; Linux (Conectiva) versions 7.0, 8.0. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Postfix 1.1.11-0.woody3, Postfix 1.1.12.
Brandefense priority: routine patching, as no exploitation is known and its severity is moderate or low.
Is CVE-2003-0540 On Your Attack Surface?
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