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FirefoxWeb browser · Mozilla

CVE-2015-4493

HIGH · 9.3 CVSS v2.0 Published 2015-08-16
Fix available
A fix is available. Upgrade to after 39.0.3 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
Heap-based buffer overflow in the stagefright::ESDS::parseESDescriptor function in libstagefright in Mozilla Firefox before 40.0 and Firefox ESR 38.x before 38.2 allows remote attackers to execute arbitrary code via an invalid size field in an esds chunk in MPEG-4 video data, a related issue to CVE-2015-1539.

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

Heap-based buffer overflow in libstagefright's stagefright::ESDS::parseESDescriptor function allows remote attackers to execute arbitrary code via a malformed size field in an esds chunk within MPEG-4 video data, affecting Firefox before 40.0 and Firefox ESR before 38.2.

MitigationUpdate Mozilla Firefox to version 40.0 or later, or Firefox ESR to 38.2 or later, to include the patched libstagefright component.

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:<= 39.0.3= 38.0= 38.0.1= 38.0.5= 38.1.0
Ubuntu LinuxOperating system
Affected:= 12.04= 14.04= 15.04
SolarisOperating system
Affected:= 11.3
OpensuseOperating system
Affected:= 13.1= 13.2

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
M
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:M/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. Check if Firefox is installed
    Run 'firefox --version' or look for Firefox in your installed applications
    Affected if Firefox is not found on the system, the vulnerability does not apply
  2. Identify the installed Firefox version
    Run 'firefox --version' to get the exact version number, or check Help > About Firefox in the browser
    Affected if Version is 39.0.3 or lower, or ESR version is 38.1.0 or lower
  3. Verify the libstagefright component is present
    Check for libstagefright libraries in the Firefox installation directory or system libraries used by Firefox for media parsing
    Affected if The libstagefright library is present and used by Firefox for MPEG-4 parsing

The environment is affected if Firefox version is 39.0.3 or lower (or ESR 38.1.0 or lower) and the libstagefright component is available for processing MPEG-4 video content.

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 39.0.3
Interim mitigation

Update Mozilla Firefox to version 40.0 or later, or Firefox ESR to 38.2 or later, to include the patched libstagefright component.

Recommended fix High confidence

Firefox 40.0 or later (mainline); Firefox ESR 38.2 or later (ESR branch)

  1. 1. Check current Firefox version by navigating to Help > About Firefox (or visiting about:support)
  2. 2. For Firefox (non-ESR) users: Upgrade to Firefox 40.0 or later from https://www.mozilla.org/firefox/
  3. 3. For Firefox ESR users: Upgrade to Firefox ESR 38.2 or later from https://www.mozilla.org/firefox/organizations/
  4. 4. On Linux distributions (Ubuntu 12.04, 14.04, 15.04; OpenSUSE 13.1, 13.2): Update via system package manager (apt-get update && apt-get upgrade firefox or zypper update firefox)
  5. 5. Verify the upgrade was successful by checking Help > About Firefox shows version 40.0+ or ESR 38.2+
Caveat Firefox 40.0 introduced new features and may have removed compatibility with some older extensions; Firefox ESR 38.2 is a minor update within the same major version with lower breaking change risk

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

Fix this in Firefox Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,800
Get the upgrade done

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Scan for this in your stack

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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-2015-4493 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