CVE-2026-39545
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 Zermatt <= 1.6.1 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 confidenceAn unauthenticated PHP Object Injection vulnerability in Zermatt versions 1.6.1 and below allows remote attackers to deserialize untrusted data without authentication, potentially leading to remote code execution by injecting malicious PHP objects into the application.
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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Identify Zermatt installation versionCheck the version file or header in the Zermatt installation directory. Common locations include a version.php file, composer.json, or the admin dashboard. Run: find /path/to/zermatt -name 'version*' -o -name 'composer.json' 2>/dev/null | xargs grep -i versionAffected if The installed version is 1.6.1 or lower (e.g., 1.6.0, 1.5.x, etc.)
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Locate PHP deserialization entry pointsSearch the Zermatt source code for PHP unserialize() function calls that process external input. Run: grep -rn 'unserialize' /path/to/zermatt --include='*.php'Affected if Code contains unserialize() calls that process $_GET, $_POST, $_COOKIE, or other user-supplied data without prior validation
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Identify exposed API endpoints or parametersReview Zermatt's publicly accessible PHP files for parameters that accept serialized data. Check index.php, api.php, or routing files for input sources. Inspect: cat /path/to/zermatt/public/index.phpAffected if There are URL parameters, POST bodies, or cookies that pass unsanitized data to deserialization functions without authentication
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Verify authentication is not enforced on the vulnerable endpointTest the identified deserialization endpoint without providing credentials. Attempt a request like: curl -X POST 'http://target/zermatt/endpoint' -d 'data=serialized_payload'Affected if The endpoint processes the deserialized data without requiring any authentication token or session
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Confirm PHP garbage collection settingsCheck PHP configuration for deserialization security settings. Review phpinfo() output or php.ini for: unserialize_callback_func and allow_url_fopen/allow_url_include settingsAffected if unserialize_callback_func is not set to a safe handler, or if the application uses PHP versions below 8.0 that have known deserialization gadget chains
You are affected if Zermatt version is 1.6.1 or below AND the application contains accessible unserialize() calls processing unauthenticated user input.
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 Zermatt to a version newer than 1.6.1. If no patched version is available, disable the application or implement web application firewall rules to block malicious deserialization payloads until a vendor patch is released.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 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 $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-39545 — 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-2026-39545 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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