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FirefoxWeb browser · Mozilla

CVE-2013-5603

HIGH · 10.0 CVSS v2.0 Published 2013-10-30
Fix available
A fix is available. Upgrade to after 24.0.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Use-after-free vulnerability in the nsContentUtils::ContentIsHostIncludingDescendantOf function in Mozilla Firefox before 25.0, Firefox ESR 24.x before 24.1, Thunderbird before 24.1, and SeaMonkey before 2.22 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via vectors involving HTML document templates.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A use-after-free vulnerability in Mozilla's nsContentUtils::ContentIsHostIncludingDescendantOf function allows remote attackers to execute arbitrary code or cause heap memory corruption via specially crafted HTML document templates. The vulnerability stems from accessing freed heap memory when processing document templates, enabling potential code execution.

MitigationUpgrade affected products to Firefox 25.0+, Firefox ESR 24.1+, Thunderbird 24.1+, or SeaMonkey 2.22+ to patch the vulnerability. Network-based mitigations like disabling HTML rendering in untrusted contexts may reduce exposure.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FirefoxWeb browser
Affected:= 24.0= 24.0.1= 24.0.2<= 24.0= 19.0= 19.0.1= 19.0.2= 20.0= 20.0.1= 21.0= 22.0= 23.0
ThunderbirdApplication
Affected:<= 24.0.1= 17.0= 17.0.1= 17.0.2= 17.0.3= 17.0.4= 17.0.5= 17.0.6= 17.0.7= 17.0.8= 24.0
Thunderbird EsrApplication
Affected:= 17.0.9
SeamonkeyApplication
Affected:<= 2.22= 2.0= 2.0.1= 2.0.2= 2.0.3= 2.0.4= 2.0.5= 2.0.6= 2.0.7= 2.0.8= 2.0.9= 2.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Mozilla product
    Check which Mozilla application is installed by looking for Firefox, Thunderbird, or SeaMonkey in your installed programs. On Linux, run 'which firefox thunderbird seamonkey' or check /usr/bin/. On Windows, check Program Files for Mozilla folders. On macOS, check /Applications for Firefox.app, Thunderbird.app, or SeaMonkey.app.
    Affected if Any of these three products is installed
  2. Determine Firefox version
    If Firefox is installed, type 'about:support' in the address bar and look for 'Version' in the page, or run 'firefox --version' from command line.
    Affected if Version is 19.0, 19.0.1, 19.0.2, 20.0, 20.0.1, 21.0, 22.0, 23.0, 24.0, 24.0.1, or 24.0.2
  3. Determine Thunderbird version
    If Thunderbird is installed, go to Help > About Thunderbird, or run 'thunderbird --version' from command line.
    Affected if Version is 17.0 through 17.0.9, 24.0, or 24.0.1
  4. Determine SeaMonkey version
    If SeaMonkey is installed, go to Help > About SeaMonkey, or run 'seamonkey --version' from command line.
    Affected if Version is 2.0 through 2.22 inclusive
  5. Check if vulnerable feature is in use
    The vulnerability triggers when processing specially crafted HTML document templates. Review any web content or email handling that processes untrusted HTML templates. In enterprise environments, check proxy logs or email gateways for unusual template processing.
    Affected if The product processes HTML document templates from untrusted sources

Your environment is affected if you have Firefox 19.0-24.0.2, Thunderbird 17.x or 24.0-24.0.1, or SeaMonkey 2.0-2.22 installed and those applications process HTML document templates.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 24.0.1
Interim mitigation

Upgrade affected products to Firefox 25.0+, Firefox ESR 24.1+, Thunderbird 24.1+, or SeaMonkey 2.22+ to patch the vulnerability. Network-based mitigations like disabling HTML rendering in untrusted contexts may reduce exposure.

Recommended fix High confidence

Firefox 25.0+ (or Firefox ESR 24.1+), Thunderbird 24.1+, or SeaMonkey 2.22+ depending on product

  1. 1. Identify which Mozilla product is installed (Firefox, Thunderbird, or SeaMonkey) and the current version by checking the application's 'About' section or running 'firefox --version', 'thunderbird --version', or 'seamonkey --version'
  2. 2. If running Firefox 24.x (versions 24.0, 24.0.1, 24.0.2) or earlier, upgrade to Firefox 25.0 or later
  3. 3. If running Firefox ESR 24.x, upgrade to Firefox ESR 24.1 or later
  4. 4. If running Thunderbird 24.0.1 or earlier, or Thunderbird 17.x, upgrade to Thunderbird 24.1 or later
  5. 5. If running SeaMonkey 2.22 or earlier, upgrade to SeaMonkey 2.22 or later
  6. 6. After upgrading, restart the application and verify the version is correct
Caveat Standard version upgrade; no major breaking changes expected for end users

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2013-5603 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data