Vulnerability record · CVE-2003-0309 · published 9 June 2003
CVE-2003-0309: Internet Explorer security zone bypass via file download dialogs
Microsoft · Internet Explorer
Internet Explorer 5.01, 5.5, and 6.0 can be tricked into bypassing security zone restrictions and executing arbitrary programs. A web document containing many duplicate file:// or similar requests opens multiple file download dialogs, eventually causing IE to execute the referenced program.
Description
Internet Explorer 5.01, 5.5, and 6.0 allows remote attackers to bypass security zone restrictions and execute arbitrary programs via a web document with a large number of duplicate file:// or other requests that point to the program and open multiple file download dialogs, which eventually cause Internet Explorer to execute the program, as demonstrated using a large number of FRAME or IFRAME tags, aka the "File Download Dialog Vulnerability."
AV:N/AC:L/Au:N/C:P/I:P/A:P
Automated analysis
high priorityRemote, unauthenticated code execution with high EPSS despite no KEV listing, and the affected product is legacy but may still exist in isolated environments.
What it is
Internet Explorer 5.01, 5.5, and 6.0 can be tricked into bypassing security zone restrictions and executing arbitrary programs. A web document containing many duplicate file:// or similar requests opens multiple file download dialogs, eventually causing IE to execute the referenced program.
Impact
An attacker can bypass IE security zones and run arbitrary programs on the victim's machine, leading to full compromise of confidentiality, integrity, and availability.
Attack surface
Reached over the network by viewing a malicious web document; no authentication is required, but the victim must open the page in a vulnerable IE version. The CVSS vector AV:N/AC:L/Au:N confirms remote, unauthenticated access.
Exploitation
Not listed in CISA KEV and no exploit tags are present in the references, but EPSS is high (0.4997, 98.8th percentile), indicating elevated likelihood of exploitation activity.
What to do
- Apply Microsoft security bulletin MS03-020 or the corresponding IE cumulative update.
- Upgrade to a supported, non-vulnerable version of Internet Explorer or a modern browser.
- Disable or restrict file download dialogs and file:// handling in IE where feasible.
- Block untrusted web content and enforce network-level filtering for known malicious pages.
Detection
- Monitor for IE processes spawning unexpected child processes or executables.
- Alert on web pages containing unusually large numbers of FRAME or IFRAME tags referencing file:// or download dialogs.
- Review proxy and web logs for requests matching known exploit patterns for this vulnerability.
This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
Track CVE-2003-0309 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2003-0309), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
