CVE-2004-0121Outlook Vulnerability
Argument injection vulnerability in Microsoft Outlook 2002 does not sufficiently filter parameters of mailto: URLs when using them as arguments when calling OUTLOOK.EXE, which allows remote attackers to use script code in the Local Machine zone and execute arbitrary programs.
Published Apr 15, 2004 · Updated Apr 15, 2026
Key Facts
Patch immediately- CVE-2004-0121 is a high-severity vulnerability (CVSS 7.5 v2) affecting Office (Microsoft), Outlook (Microsoft).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 48% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v2
7.5
AV:N/AC:L/Au:N/C:P/I:P/A:P
EPSS (30-day exploit likelihood)
48%
Higher than 98.8% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
46/100
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
1
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
- advisory20040310 Outlook mailto: URL argument injection vulnerability
- advisoryoutlook-mailtourl-execute-code(15414)
- advisoryoutlook-ms04009-patch(15429)
- advisoryVU#305206
- advisoryTA04-070A
- patchMS04-009
Description
Argument injection vulnerability in Microsoft Outlook 2002 does not sufficiently filter parameters of mailto: URLs when using them as arguments when calling OUTLOOK.EXE, which allows remote attackers to use script code in the Local Machine zone and execute arbitrary programs.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| OfficeMicrosoft | xp-sp2 | n/a |
| OutlookMicrosoft | 2002-sp2 | n/a |
Timeline
Publicly disclosed
Apr 15, 2004
Last updated
Apr 15, 2026
Weakness Type
- CWE-88 Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
References
- advisory20040310 Outlook mailto: URL argument injection vulnerability
- advisoryoutlook-mailtourl-execute-code(15414)
- advisoryoutlook-ms04009-patch(15429)
- advisoryVU#305206
- advisoryTA04-070A
FAQ
Common Questions.
Argument injection vulnerability in Microsoft Outlook 2002 does not sufficiently filter parameters of mailto: URLs when using them as arguments when calling OUTLOOK.EXE, which allows remote attackers to use script code in the Local Machine zone and execute arbitrary programs.
Affected: Office (Microsoft) versions xp-sp2; Outlook (Microsoft) versions 2002-sp2. 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.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Is CVE-2004-0121 On Your Attack Surface?
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