ChromeWeb browser · Google
CVE-2015-6778
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 · uneditedThe CJBig2_SymbolDict class in fxcodec/jbig2/JBig2_SymbolDict.cpp in PDFium, as used in Google Chrome before 47.0.2526.73, allows remote attackers to cause a denial of service (out-of-bounds memory access) or possibly have unspecified other impact via a PDF document containing crafted data with JBIG2 compression.
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 confidenceThe CJBig2_SymbolDict class in PDFium's JBIG2 decoder (fxcodec/jbig2/JBig2_SymbolDict.cpp) lacks proper bounds validation when processing JBIG2 compressed data in PDF documents. This allows specially crafted PDF files to trigger out-of-bounds memory access, leading to denial of service or potentially code execution.
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
ChromeWeb browser
<= 46.0.2490.86CVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/A:P
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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Check your Google Chrome versionOpen chrome://version in the Chrome address bar and note the version number shown after 'Google Chrome'Affected if The version listed is 46.0.2490.86 or lower (for example, 46.0.2490.80, 45.x.x.x, etc.)
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Confirm PDF viewing capability is enabledNavigate to chrome://settings and search for 'PDF' to verify 'Download PDF files instead of automatically opening them in Chrome' is unchecked, meaning PDFs open internally using PDFiumAffected if PDFs open in Chrome's built-in PDF viewer (this is the default setting)
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Identify if you open PDF documents with JBIG2 contentThis vulnerability triggers when opening a specially crafted PDF containing JBIG2 compressed data; there is no simple command to detect JBIG2 in existing PDFs without analyzing the file structure with a hex editor or PDF parserAffected if You routinely open PDF documents from untrusted sources (such as email attachments or web downloads) and the PDF contains JBIG2 image data
You are affected if your Chrome version is 46.0.2490.86 or lower AND you open a maliciously crafted PDF containing JBIG2 data, which triggers the out-of-bounds memory access in PDFium's CJBig2_SymbolDict class.
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 Google Chrome to version 47.0.2526.73 or later which includes the patched PDFium library; alternatively, update the PDFium component to a version containing the bounds-checking fix in CJBig2_SymbolDict.
Fix this in Chrome
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-6778 — 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-2015-6778 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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