PHPApplication
CVE-2017-12934
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 · uneditedext/standard/var_unserializer.re in PHP 7.0.x before 7.0.21 and 7.1.x before 7.1.7 is prone to a heap use after free while unserializing untrusted data, related to the zval_get_type function in Zend/zend_types.h. Exploitation of this issue can have an unspecified impact on the integrity of PHP.
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 · moderate confidenceHeap use-after-free vulnerability in PHP's var_unserializer component when processing untrusted serialized data. The flaw exists in the zval_get_type function within Zend/zend_types.h, allowing memory corruption during unserialization operations.
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
PHPApplication
= 7.0.0= 7.0.1= 7.0.2= 7.0.3= 7.0.4= 7.0.5= 7.0.6= 7.0.7= 7.0.8= 7.0.9= 7.0.10= 7.0.11CVSS 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
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 PHP versionRun 'php -v' or 'phpinfo()' to display the installed PHP versionAffected if The version is 7.0.0, 7.0.1, 7.0.2, 7.0.3, 7.0.4, 7.0.5, 7.0.6, 7.0.7, 7.0.8, 7.0.9, 7.0.10, or 7.0.11
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Identify unserialize() usage in codeSearch PHP source files for 'unserialize(' function calls using grep or similar toolsAffected if The application calls unserialize() to process serialized data
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Verify source of serialized dataInspect code paths where unserialize() is called and determine if input originates from untrusted external sources such as user input, HTTP requests, databases, or network connectionsAffected if unserialize() processes data from untrusted or external sources without validation
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Check for object unserialize handlersReview code for use of PHP's var_unserializer or custom unserialize handlers, and search for magic methods __wakeup or __destruct in classes that handle deserialized objectsAffected if Custom unserialize handlers or classes with __wakeup/__destruct methods process untrusted serialized data
You are affected if you run PHP version 7.0.0 through 7.0.11 AND your application uses unserialize() to process data from untrusted sources.
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 PHP to version 7.0.21 or later (7.0.x) or 7.1.7 or later (7.1.x). Additionally, avoid using unserialize() on untrusted data and consider using JSON instead of PHP's native serialization.
Fix this in PHP
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-12934 — 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-2017-12934 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
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