# What is CVE-2004-0839?

> CVE-2004-0839 is a medium-severity flaw (CVSS 5.0) in Internet Explorer from Microsoft, published on 18 August 2004. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 34%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2004-0839

## At a glance

- **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
- **Precursor Intelligence risk score:** 40 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** Medium (CVSS 5.0 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 34% (latest exploit-likelihood forecast)
- **Published:** 18 August 2004
- **Record last updated:** 16 June 2026
- **Main product:** Internet Explorer from Microsoft
- **Affected products:** 18

## What is CVE-2004-0839? In plain terms

It can be attacked from anywhere on the internet without logging in. If it works, the attacker can change some data.

### The official description

Internet Explorer in Windows XP SP2, and other versions including 5.01 and 5.5, allows remote attackers to install arbitrary programs via a web page that uses certain styles and the AnchorClick behavior, popup windows, and drag-and-drop capabilities to drop the program in the local startup folder, as demonstrated by "wottapoop.html".

### What kind of flaw is it?

- Unknown: Unknown

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Easy: no special conditions
- Login needed first: No login needed
- What an attacker gets: Can change some data

Severity vector: `AV:N/AC:L/Au:N/C:N/I:P/A:N`

## Is CVE-2004-0839 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 34%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 34%, 34%, 34%, 34%, 34%, 34%, 34%.

### Timeline

- 18 August 2004: Published
- 16 June 2026: Exploit likelihood fell
- 16 June 2026: Record last updated

### How Precursor Intelligence ranks it

CVE-2004-0839 scores **40 out of 100 (Medium)**, with the action "Plan remediation".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: key context
- Real threat activity around it: key context

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2004-0839?

The published record lists 18 products.

- [Internet Explorer](https://www.precursorintelligence.com/product/microsoft/internet_explorer) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Application): 5.0.1, 5.0.1-sp1, 5.0.1-sp2, 5.0.1-sp3, 5.0.1-sp4, 5.5, 5.5-sp1, 5.5-sp2, 6.0
- [Windows 2003 Server](https://www.precursorintelligence.com/product/microsoft/windows_2003_server) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): enterprise, enterprise_64-bit, r2, standard, web
- [Ie](https://www.precursorintelligence.com/product/microsoft/ie) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Application): 6.0-sp1, 6.0-sp2
- [Modular Messaging Message Storage Server](https://www.precursorintelligence.com/product/avaya/modular_messaging_message_storage_server) by [Avaya](https://www.precursorintelligence.com/vendors/avaya) (Operating system): 1.1, 2.0
- [Definity One Media Server](https://www.precursorintelligence.com/product/avaya/definity_one_media_server) by [Avaya](https://www.precursorintelligence.com/vendors/avaya) (Hardware): all versions
- [IP Softphone 2050](https://www.precursorintelligence.com/product/nortel/ip_softphone_2050) by [Nortel](https://www.precursorintelligence.com/vendors/nortel) (Application): all versions
- [Ip600 Media Servers](https://www.precursorintelligence.com/product/avaya/ip600_media_servers) by [Avaya](https://www.precursorintelligence.com/vendors/avaya) (Application): all versions
- [Mobile Voice Client 2050](https://www.precursorintelligence.com/product/nortel/mobile_voice_client_2050) by [Nortel](https://www.precursorintelligence.com/vendors/nortel) (Application): all versions
- [Optivity Telephony Manager](https://www.precursorintelligence.com/product/nortel/optivity_telephony_manager) by [Nortel](https://www.precursorintelligence.com/vendors/nortel) (Application): all versions
- [S3400](https://www.precursorintelligence.com/product/avaya/s3400) by [Avaya](https://www.precursorintelligence.com/vendors/avaya) (Hardware): all versions
- [S8100](https://www.precursorintelligence.com/product/avaya/s8100) by [Avaya](https://www.precursorintelligence.com/vendors/avaya) (Hardware): all versions
- [Symposium Web Centre Portal](https://www.precursorintelligence.com/product/nortel/symposium_web_centre_portal) by [Nortel](https://www.precursorintelligence.com/vendors/nortel) (Application): all versions
- [Symposium Web Client](https://www.precursorintelligence.com/product/nortel/symposium_web_client) by [Nortel](https://www.precursorintelligence.com/vendors/nortel) (Application): all versions
- [Windows 2000](https://www.precursorintelligence.com/product/microsoft/windows_2000) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): all versions
- [Windows 98](https://www.precursorintelligence.com/product/microsoft/windows_98) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): all versions
- [Windows 98se](https://www.precursorintelligence.com/product/microsoft/windows_98se) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): all versions
- [Windows Me](https://www.precursorintelligence.com/product/microsoft/windows_me) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): all versions
- [Windows Xp](https://www.precursorintelligence.com/product/microsoft/windows_xp) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): all versions

## How do I fix CVE-2004-0839?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [kb.cert.org](http://www.kb.cert.org/vuls/id/526089) (Patch, Third-party advisory, Government resource)
- [securityfocus.com](http://www.securityfocus.com/bid/10973) (Exploit, Patch, Vendor advisory)
- [us-cert.gov](http://www.us-cert.gov/cas/techalerts/TA04-293A.html) (Patch, Third-party advisory, Government resource)
- [seclists.org](http://seclists.org/lists/fulldisclosure/2004/Aug/0868.html) (Vendor advisory)
- [marc.info](http://marc.info/?l=bugtraq&m=109303291513335&w=2)
- [marc.info](http://marc.info/?l=bugtraq&m=109336221826652&w=2)
- [docs.microsoft.com](https://docs.microsoft.com/en-us/security-updates/securitybulletins/2004/ms04-038)
- [exchange.xforce.ibmcloud.com](https://exchange.xforce.ibmcloud.com/vulnerabilities/17044)
- [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A1563)
- [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A2073)
- [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A3773)
- [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A4152)
- [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6272)
- [oval.cisecurity.org](https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A7721)

## Questions

### What is CVE-2004-0839?

CVE-2004-0839 is a medium-severity flaw in Internet Explorer from Microsoft, published on 18 August 2004. It can be attacked from anywhere on the internet without logging in. If it works, the attacker can change some data.

### How serious is CVE-2004-0839?

It scores 5.0 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2004-0839 is 40 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

### Is CVE-2004-0839 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 34%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2004-0839 affect?

For Internet Explorer from Microsoft: 5.0.1, 5.0.1-sp1, 5.0.1-sp2, 5.0.1-sp3, 5.0.1-sp4, 5.5 and 3 more. The record lists 18 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2004-0839?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2004-0839 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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