CVE-2026-39556
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 · uneditedUnauthenticated PHP Object Injection in Konsept <= 1.9 versions.
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 confidenceUnauthenticated PHP Object Injection in Konsept <= 1.9 allows remote attackers to inject malicious PHP objects via unsafe deserialization of user-controlled input, potentially leading to remote code execution if appropriate PHP gadget chains exist in the application or its dependencies.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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 checksWork through these to decide whether this CVE applies to you.
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Determine installed Konsept versionCheck the version file or header in the application root (commonly version.php, composer.json, or a VERSION constant)Affected if Version is 1.9 or lower, indicating the application is within the vulnerable range
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Locate unserialize() calls handling user inputSearch the codebase for patterns like unserialize($_GET, unserialize($_POST, unserialize($_COOKIE, or unserialize($_REQUESTAffected if Any unserialize() call directly uses input from $_GET, $_POST, $_COOKIE, or $_REQUEST without prior sanitization or validation
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Identify PHP magic methods in application codeSearch for classes containing __wakeup, __destruct, __toString, or __invoke methods which could serve as gadget chain anchorsAffected if The application or its dependencies contain magic methods that could be chained with unserialize() for RCE
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Verify authentication is required for the deserialization entry pointReview the script or endpoint performing the deserialization to confirm whether it is accessible without authenticationAffected if The vulnerable deserialization occurs in an unauthenticated code path (no login or session validation required)
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Check for presence of exploitable gadget chainsReview composer.json and installed dependencies for known PHP gadget libraries (like Symfony, Laravel, Doctrine, Monolog) that have documented unserialize gadget chainsAffected if The application uses dependencies with known unserialize gadget chains that could enable remote code execution
If the installed version is 1.9 or lower AND the application uses unserialize() on unauthenticated user input AND exploitable gadget chains exist in the application or dependencies, the environment is vulnerable to remote code execution via this CVE.
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 Konsept to the latest patched version. If no patch is available, audit the codebase for uses of unserialize() on user input and replace with safer alternatives like json_decode(), or implement strict allowlist validation before deserialization.
- Consultation3.0 h
- Implementation6.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-39556 — 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-2026-39556 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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