Ubuntu LinuxOperating system · Canonical

CVE-2015-4486

HIGH · 10.0 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

NVD · unedited

The decrease_ref_count function in libvpx in Mozilla Firefox before 40.0 and Firefox ESR 38.x before 38.2 allows remote attackers to execute arbitrary code or cause a denial of service (out-of-bounds read) via malformed WebM video data.

Technical summary

dbcve analysis · high confidence

A vulnerability exists in the libvpx library (VP8/VP9 video codec) in Mozilla Firefox before 40.0 and Firefox ESR 38.x before 38.2. The decrease_ref_count function fails to properly handle malformed WebM video data, allowing remote attackers to trigger an out-of-bounds read that can lead to arbitrary code execution or denial of service.

MitigationUpdate Mozilla Firefox to version 40.0 or later, or Firefox ESR to version 38.2 or later, to obtain the patched libvpx library.

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

Affected products & versions

NVD · CPE data

Ubuntu LinuxOperating system

Affected:= 12.04= 14.04= 15.04

FirefoxWeb browser

Affected:<= 39.0.3= 38.0= 38.0.1= 38.0.5= 38.1.0

OpensuseOperating system

Affected:= 13.1= 13.2

SolarisOperating system

Affected:= 11.3

CVSS breakdown

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?

dbcve checks

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

Determine installed Firefox version

Run 'firefox --version' from command line, or in Firefox go to Help > About Firefox

Affected if Version is 39.0.3 or earlier, or any 38.x version before 38.2 (38.0, 38.0.1, 38.0.5, 38.1.0)
Check libvpx library version on Linux

Run 'dpkg -l | grep libvpx' (Ubuntu/Debian) or 'rpm -qa | grep libvpx' (openSUSE) to list installed libvpx packages

Affected if libvpx version is present and matches the vulnerable version bundled with affected Firefox versions
Verify WebM playback is enabled

Confirm the VP8/VP9 video support module is active in Firefox by loading 'about:support' and checking for 'WebM' in Media codec information, or simply attempt to play any .webm video file

Affected if WebM/VP8/VP9 video decoding is enabled and functional in the browser
Check Firefox ESR version on enterprise systems

Run 'firefox --version' on systems running Firefox ESR, or check the package manager for ESR version installed via 'dpkg -l firefox-esr' or 'rpm -qi firefox-esr'

Affected if ESR version is 38.0, 38.0.1, 38.0.5, or 38.1.0 (versions before 38.2)

The environment is affected if Firefox (standard or ESR) version is 39.0.3 or earlier, or any 38.x version before 38.2, and the browser has WebM/VP8/VP9 video playback capability enabled.

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

Remediation

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 version 38.2 or later, to obtain the patched libvpx library.

Recommended fix High confidence

Firefox 40.0 or later / Firefox ESR 38.2 or later

Check current Firefox version by navigating to Help > About Firefox
Upgrade to Firefox 40.0 or later for standard releases
For enterprise/organizational deployments, upgrade to Firefox ESR 38.2 or later
On Ubuntu systems, run: sudo apt-get update && sudo apt-get upgrade firefox
On OpenSUSE systems, run: sudo zypper patch
On Solaris 11.3, run: pkg update firefox
Restart Firefox after applying updates
Verify the version has been updated to 40.0+ (or ESR 38.2+)

Caveat Major version upgrade may cause compatibility issues with older browser extensions; ESR versions recommended for stability

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

Fix this in Ubuntu Linux Scoped from the published advisory

Consultation4.0 h
Implementation8.0 h
Testing4.0 h
Review / QA2.0 h

18.0 hours of engineering $3,200

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Scan for this in your stack

Free · runs locally

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2015-4486 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2015-4486?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

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

At a glance

A fix existsUpgrade to after 39.0.3 or later

Severity 10.0 High

Exploit likelihood EPSS, next 30 days 6.6%

Affects: Ubuntu Linux

Remediation

A high-priority fix

Fix this in Ubuntu Linux 18 hrs · Moderate

Typical engagement from $3,200

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2015-4486 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References