FirefoxWeb browser · Mozilla
CVE-2016-5296
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 · uneditedA heap-buffer-overflow in Cairo when processing SVG content caused by compiler optimization, resulting in a potentially exploitable crash. This vulnerability affects Thunderbird < 45.5, Firefox ESR < 45.5, and Firefox < 50.
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 confidenceA heap-buffer-overflow vulnerability exists in the Cairo graphics library when processing SVG content. The flaw is triggered by a compiler optimization issue that causes memory corruption, potentially leading to arbitrary code execution or denial of service.
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
< 45.5.0< 50.0
Debian LinuxOperating system
= 8.0< 45.5.0CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Mozilla productRun 'firefox --version' or 'thunderbird --version' from command line, or check installed packages via system package managerAffected if Product is Firefox or Thunderbird and version is unpatched
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Check Firefox version against affected rangesCompare installed Firefox version to: any version < 45.5.0, OR versions 45.5.0 through 49.x (versions 50.0 and later are patched)Affected if Firefox version is below 45.5.0 OR between 45.5.0 and 49.x inclusive
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Check Thunderbird version against affected rangesCompare installed Thunderbird version to: any version < 45.5.0 is vulnerable, 45.5.0 and later are patchedAffected if Thunderbird version is below 45.5.0
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Verify SVG content can be processedCheck if the browser or mail client can render or process SVG content - this is enabled by default in Firefox and Thunderbird for HTML emails and web contentAffected if SVG rendering is enabled (default state) and product version is vulnerable as checked above
User is affected if running Firefox < 45.5.0 or Firefox 45.5.0-49.x or Thunderbird < 45.5.0, with SVG content processing enabled (default configuration).
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 data45.5.050.0
Upgrade affected Mozilla products to the patched versions: Thunderbird and Firefox ESR to 45.5+, or Firefox to 50+. Alternatively, disable or restrict SVG content processing in untrusted contexts until patching is possible.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-5296 — 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-2016-5296 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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- 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
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