LinuxOperating system · Oracle
CVE-2016-5265
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 · uneditedMozilla Firefox before 48.0 and Firefox ESR 45.x before 45.3 allow user-assisted remote attackers to bypass the Same Origin Policy, and conduct Universal XSS (UXSS) attacks or read arbitrary files, by arranging for the presence of a crafted HTML document and a crafted shortcut file in the same local directory.
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 confidenceMozilla Firefox before 48.0 and Firefox ESR 45.x before 45.3 contain a Same Origin Policy bypass vulnerability where a crafted HTML document paired with a malicious shortcut file (e.g., .url, .lnk) in the same local directory enables an attacker to conduct Universal XSS (UXSS) attacks or read arbitrary files on the local system. The attack is user-assisted, requiring the victim to interact with the malicious files.
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
LinuxOperating system
= 5.0= 6= 7
FirefoxWeb browser
<= 47.0.1= 45.1.0= 45.1.1= 45.2.0= 45.3.0CVSS 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
- Local
- Complexity
- High
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Determine installed Firefox versionOpen Firefox, click the menu button, select Help, then About Firefox. Alternatively, run 'firefox --version' from command line.Affected if Version is 47.0.1 or earlier, or any 45.x version before 45.3.0 (45.1.0, 45.1.1, 45.2.0, 45.3.0)
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Confirm Firefox ESR statusCheck if the installed Firefox is the Extended Support Release (ESR) variant by looking for 'ESR' in the About dialog or running 'firefox --version' which may display ESR in the output.Affected if Running Firefox ESR 45.x versions before 45.3
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Verify same-directory shortcut handlingThis is a browser behavior: attempt to load a local .url or .lnk file from a directory containing a maliciously crafted HTML document. The vulnerability triggers when the browser processes the shortcut file and allows the HTML content to execute with elevated privileges.Affected if Browser can be coaxed into loading and rendering local shortcut files (.url, .lnk) alongside HTML documents in the same directory
You are affected if Firefox version is 47.0.1 or earlier, or Firefox ESR 45.1.0 through 45.3.0, and the browser processes local shortcut files from the same directory as HTML content.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade Firefox to version 48.0 or later, or Firefox ESR to 45.3 or later, to obtain the patched browser versions that address this SOP bypass.
Fix this in Linux
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 h
- Review / QA1.0 h
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
Free · runs locallyCheck whether your project pulls in CVE-2016-5265 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2016-5265 in production — separate from our analysis above.
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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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.
- 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