Not ratedCVE-2006-4253

    Mozilla Firefox: Denial of Service (CVE-2006-4253)

    Published Sources: CVE.org

    What is affected, what to do

    Concurrency vulnerability in Mozilla Firefox 1.5.0.6 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via multiple Javascript timed events that load a deeply nested XML file, followed by redirecting the browser to another page, which leads to a concurrency failure that causes structures to be freed incorrectly, as demonstrated by (1) ffoxdie and (2) ffoxdie3. NOTE: it has been reported that Netscape 8.1 and K-Meleon 1.0.1 are also affected by ffoxdie.

    The available sources name no fixed version. Check the vendor guidance in the references below.

    Affected
    • K-meleon eq 1.0.1..1.0.1
    • Mozilla Firefox eq 0.8..0.8
    • Mozilla Firefox eq 0.9..0.9
    • Mozilla Firefox eq 0.9.1..0.9.1
    • Mozilla Firefox eq 0.9.2..0.9.2
    • Mozilla Firefox eq 0.9.3..0.9.3
    • Mozilla Firefox eq 0.10..0.10
    • Mozilla Firefox eq 0.10.1..0.10.1
    • Mozilla Firefox eq 1.0..1.0
    • Mozilla Firefox eq 1.0.1..1.0.1
    • Mozilla Firefox eq 1.0.2..1.0.2
    • Mozilla Firefox eq 1.0.3..1.0.3
    • Mozilla Firefox eq 1.0.4..1.0.4
    • Mozilla Firefox eq 1.0.5..1.0.5
    • Mozilla Firefox eq 1.0.6..1.0.6
    • Mozilla Firefox eq 1.0.7..1.0.7
    • Mozilla Firefox eq 1.0.8..1.0.8
    • Mozilla Firefox eq 1.5..1.5
    • Mozilla Firefox eq 1.5.0.1..1.5.0.1
    • Mozilla Firefox eq 1.5.0.2..1.5.0.2
    • Mozilla Firefox eq 1.5.0.3..1.5.0.3
    • Mozilla Firefox eq 1.5.0.4..1.5.0.4
    • Mozilla Firefox eq 1.5.0.5..1.5.0.5
    • Mozilla Firefox eq 1.5.0.6..1.5.0.6
    • Netscape Navigator Navigator eq 8.1..8.1

    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.

    15.2 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 96.7

    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
    74.87 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
    15.2 %
    Elevated — model estimates 10-50% exploitation likelihood.
    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
    96.7
    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

    Concurrency vulnerability in Mozilla Firefox 1.5.0.6 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via multiple Javascript timed events that load a deeply nested XML file, followed by redirecting the browser to another page, which leads to a concurrency failure that causes structures to be freed incorrectly, as demonstrated by (1) ffoxdie and (2) ffoxdie3. NOTE: it has been reported that Netscape 8.1 and K-Meleon 1.0.1 are also affected by ffoxdie. Mozilla confirmed to CVE that ffoxdie and ffoxdie3 trigger the same underlying vulnerability. NOTE: it was later reported that Firefox 2.0 RC2 and 1.5.0.7 are also affected.

    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 products
    Affected versionsFixed in
    k-meleon_projectk-meleon
    • 1.0.1
    • —
    mozillafirefox
    • 1.5.0.2
    • 1.0.1
    • 1.5
    • 1.0.3
    • 0.9.1
    • 1.0.2
    • 1.0
    • 1.5.0.3
    • 0.8
    • 1.5.0.5
    • 1.5.0.6
    • 0.9
    • 1.0.7
    • 1.5.0.4
    • 0.9.2
    • 0.10
    • 0.9.3
    • 1.0.8
    • 1.5.0.1
    • 1.0.6
    • 1.0.5
    • 0.10.1
    • 1.0.4
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    netscapenavigator
    • 8.1
    • —

    Vendors and products

    References & sources

    • securityfocus.com20061017 Flaw in Firefox 2.0 RC2Mailing list, x_refsource_BUGTRAQ
    • securityfocus.com20060817 Re: [VulnWatch] Re: Concurrency-related vulnerabilities in browsers - expect problemsMailing list, x_refsource_BUGTRAQ
    • securitytracker.com1016847Vulnerability database, x_refsource_SECTRACK
    • secunia.com22391Third-party advisory, x_refsource_SECUNIA
    • vupen.comADV-2006-3748Vulnerability database, x_refsource_VUPEN
    • redhat.comRHSA-2006:0676Vendor advisory, x_refsource_REDHAT
    • mozilla.orgsecurity/announce/2006/mfsa2006-59.htmlx_refsource_CONFIRM
    • lcamtuf.coredump.cxffoxdie.htmlx_refsource_MISC
    • secunia.com22055Third-party advisory, x_refsource_SECUNIA
    • secunia.com22195Third-party advisory, x_refsource_SECUNIA
    • oval.cisecurity.orgoval:org.mitre.oval:def:9528Vulnerability database, signature, x_refsource_OVAL
    • ubuntu.comUSN-352-1Vendor advisory, x_refsource_UBUNTU
    • secunia.com21513Third-party advisory, x_refsource_SECUNIA
    • secunia.com21950Third-party advisory, x_refsource_SECUNIA
    • ubuntu.comUSN-351-1Vendor advisory, x_refsource_UBUNTU
    • secunia.com22025Third-party advisory, x_refsource_SECUNIA
    • secunia.com22056Third-party advisory, x_refsource_SECUNIA
    • mandriva.comMDKSA-2006:168Vendor advisory, x_refsource_MANDRIVA
    • securityfocus.com20060812 Concurrency-related vulnerabilities in browsers - expect problemsMailing list, x_refsource_BUGTRAQ
    • secunia.com22210Third-party advisory, x_refsource_SECUNIA
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