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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 15 Jun 2022.
FirefoxWeb browser · Mozilla

CVE-2015-4495

HIGH · 8.8 CVSS v3.1 Published 2015-08-08
Fix available
A fix is available. Upgrade to 2.2 / 38.1.1 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable No privileges Patch available

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
The PDF reader in Mozilla Firefox before 39.0.3, Firefox ESR 38.x before 38.1.1, and Firefox OS before 2.2 allows remote attackers to bypass the Same Origin Policy, and read arbitrary files or gain privileges, via vectors involving crafted JavaScript code and a native setter, as exploited in the wild in August 2015.

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 Same Origin Policy bypass vulnerability in Mozilla Firefox's PDF reader allows remote attackers to read arbitrary files or gain privileges via crafted JavaScript code exploiting a native setter. The vulnerability was actively exploited in the wild in August 2015.

MitigationUpdate Firefox to version 39.0.3 or later, Firefox ESR to 38.1.1 or later, or Firefox OS to 2.2 or later to patch the vulnerability.

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, < 38.1.1
Firefox OsOperating system
Affected:< 2.2
Ubuntu LinuxOperating system
Affected:= 12.04= 14.04= 15.04
Enterprise Linux DesktopOperating system
Affected:= 5.0= 6.0= 7.0
Enterprise Linux EusOperating system
Affected:= 6.7= 7.1= 7.2= 7.3= 7.4= 7.5= 7.6= 7.7
Enterprise Linux ServerOperating system
Affected:= 5.0= 6.0= 7.0
Enterprise Linux Server AusOperating system
Affected:= 7.3= 7.4= 7.6= 7.7
Enterprise Linux Server TusOperating system
Affected:= 7.3= 7.6= 7.7

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
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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 Firefox browser version
    Open Firefox and navigate to Help > About Firefox, or run 'firefox --version' from command line. Also check 'about:support' in the address bar for detailed version info.
    Affected if Version is < 39.0.3, or is >= 38.0 but < 38.1.1 (ESR versions)
  2. Confirm PDF reader component is in use
    Navigate to about:preferences#general in Firefox and locate the 'PDF Documents' section. Check if 'Preview in Firefox' is selected (the built-in PDF.js reader).
    Affected if The built-in PDF viewer (PDF.js) is enabled; the vulnerability exists in this component
  3. Check Firefox OS version on mobile devices
    On Firefox OS devices, go to Settings > About Phone > Software Update or check the device documentation for the Firefox OS version.
    Affected if Firefox OS version is < 2.2
  4. Verify Linux distribution package versions
    On Ubuntu systems run 'dpkg -l | grep firefox' or 'apt-cache policy firefox'. On RHEL systems run 'rpm -qa | grep firefox' or 'yum info firefox'.
    Affected if The packaged Firefox version matches the affected version ranges for the respective distribution

You are affected if you run any Firefox version before 39.0.3 (or ESR before 38.1.1) or Firefox OS before 2.2, and have the built-in PDF viewer enabled.

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 2.2 / 38.1.1 / 39.0.3 or later
Fixed in 2.238.1.139.0.3
Vendor patch www.oracle.com →
Interim mitigation

Update Firefox to version 39.0.3 or later, Firefox ESR to 38.1.1 or later, or Firefox OS to 2.2 or later to patch the vulnerability.

Recommended fix High confidence

Firefox 39.0.3 (or later) / Firefox ESR 38.1.1 (or later) / Firefox OS 2.2 (or later)

  1. Upgrade Firefox to version 39.0.3 or later for the release channel
  2. If using Firefox ESR, upgrade to version 38.1.1 or later
  3. For Firefox OS devices, upgrade to version 2.2 or later
  4. On Linux systems (Ubuntu 12.04, 14.04, 15.04 or Enterprise Linux variants), apply the vendor security update through your system package manager (e.g., apt-get update && apt-get upgrade firefox, or yum update firefox)

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

Fix this in Firefox Exploited in the wild — priority engagement
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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-2015-4495 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