Microsoft Internet Explorer 11: Heap-Based Buffer Overflow (CVE-2004-0842)
Published Sources: CVE.org
What is affected, what to do
Internet Explorer 6.0 SP1 and earlier, and possibly other versions, allows remote attackers to cause a denial of service (application crash from "memory corruption") via certain malformed Cascading Style Sheet (CSS) elements that trigger heap-based buffer overflows, as demonstrated using the "<STYLE>@;/*" string, possibly due to a missing comment terminator that may cause an invalid length to trigger a large memory copy operation, aka the "CSS Heap Memory Corruption Vulnerability."
The available sources name no fixed version. Check the vendor guidance in the references below.
- Affected
- Microsoft Ie
eq 6.0..6.0 - Microsoft Internet Explorer 11
eq 5.0.1..5.0.1 - Microsoft Internet Explorer 11
eq 5.5..5.5 - Microsoft Internet Explorer 11
eq 6.0..6.0 - Avaya Modular Messaging Message Storage Server
eq 1.1..1.1 - Avaya Modular Messaging Message Storage Server
eq 2.0..2.0
- Microsoft Ie
Not sure whether and how you are affected? Ask a question about this vulnerability
Metrics
—
Priority
No value is available for this vulnerability.
—
CVSS v3
No value is available for this vulnerability.
56.6 %
EPSS score
High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
Source: FIRST EPSS, percentile 99.06
Show all metrics
- Severity
- Not rated
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 78.50 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 56.6 %
- High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 99.06
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Internet Explorer 6.0 SP1 and earlier, and possibly other versions, allows remote attackers to cause a denial of service (application crash from "memory corruption") via certain malformed Cascading Style Sheet (CSS) elements that trigger heap-based buffer overflows, as demonstrated using the "<STYLE>@;/*" string, possibly due to a missing comment terminator that may cause an invalid length to trigger a large memory copy operation, aka the "CSS Heap Memory Corruption Vulnerability."
Source: cvelistv5, NVD (NIST)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| avaya | definity_one_media_server |
|
|
| avaya | ip600_media_servers |
|
|
| avaya | s3400 |
|
|
| avaya | s8100 |
|
|
| microsoft | ie |
|
|
| microsoft | internet_explorer |
|
|
Vendors and products
Affected operating systems
| Other | avaya | modular_messaging_message_storage_server | 1.1 |
| Other | avaya | modular_messaging_message_storage_server | 2.0 |
References & sources
- marc.info20040728 Re: Crash IE with 11 bytes ;)Mailing list, x_refsource_FULLDISC
- oval.cisecurity.orgoval:org.mitre.oval:def:4169Vulnerability database, signature, x_refsource_OVAL
- docs.microsoft.comMS04-038Vendor advisory, x_refsource_MS
- securiteam.comexploits/5NP042KF5A.htmlx_refsource_MISC
- kb.cert.orgVU#291304Third-party advisory, x_refsource_CERT-VN
- oval.cisecurity.orgoval:org.mitre.oval:def:2906Vulnerability database, signature, x_refsource_OVAL
- marc.info20040723 Crash IE with 11 bytes ;)Mailing list, x_refsource_FULLDISC
- ecqurity.comadv/IEstyle.htmlx_refsource_MISC
- oval.cisecurity.orgoval:org.mitre.oval:def:5592Vulnerability database, signature, x_refsource_OVAL
- exchange.xforce.ibmcloud.comie-popupshow-perform-actions(16675)Vulnerability database, x_refsource_XF
- us-cert.govTA04-293AThird-party advisory, x_refsource_CERT
- marc.info20040728 Re: Crash IE with 11 bytes ;)Mailing list, x_refsource_BUGTRAQ
- secunia.com12806Third-party advisory, x_refsource_SECUNIA
- ciac.orgP-006Third-party advisory, government-resource, x_refsource_CIAC
- securityfocus.com10816Vulnerability database, x_refsource_BID
- oval.cisecurity.orgoval:org.mitre.oval:def:6579Vulnerability database, signature, x_refsource_OVAL
- oval.cisecurity.orgoval:org.mitre.oval:def:3372Vulnerability database, signature, x_refsource_OVAL
Embed badge
Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.
<a href="https://intel.neosec.eu/en/cve/CVE-2004-0842"><img src="https://intel.neosec.eu/badge/cve/CVE-2004-0842.svg?lang=en" alt="CVE-2004-0842 – NEOSEC Intel" height="20"></a>