CVE-2025-31423
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 · uneditedDeserialization of Untrusted Data vulnerability in AncoraThemes Umberto umberto allows Object Injection.This issue affects Umberto: from n/a through <= 1.2.8.
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 confidenceThe Umberto theme contains a deserialization vulnerability where untrusted data is passed to PHP's unserialize() function, allowing attackers to inject arbitrary PHP objects. This object injection can potentially lead to remote code execution depending on available gadget chains in the application and associated plugins.
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
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/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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Locate the Umberto theme versionAccess your WordPress installation via FTP or file manager, navigate to /wp-content/themes/umberto/ and locate the style.css file. Open it and find the 'Version:' header in the file comments to read the installed version number.Affected if The version number listed is lower than the patched version released for CVE-2025-31423
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Identify PHP unserialize calls in theme filesSearch all PHP files within the /wp-content/themes/umberto/ directory for instances of 'unserialize(' function calls. Use grep or a file search utility to scan for this pattern.Affected if Any unserialize() call accepts data that originates from user input (POST, GET, COOKIE, or HTTP headers) without prior validation
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Verify the vulnerable data sourceFor each unserialize() call found, trace back the data source to determine if it receives untrusted input directly from HTTP requests. Check the surrounding code for any sanitization or validation applied before the unserialize call.Affected if The unserialize function processes data that can be controlled by an external user without cryptographic integrity checks
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Check plugin gadget chain availabilityReview all installed WordPress plugins for known PHP object injection gadget chains. Search plugin directories in /wp-content/plugins/ for classes that may be chained with the unserialize vulnerability for RCE.Affected if Plugins with exploitable gadget chains are present and the vulnerable unserialize is reachable
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Inspect HTTP endpointsIdentify which theme PHP files handle incoming HTTP requests (typically in functions.php or custom template files). Test accessing these endpoints with serialized payloads to confirm reachability.Affected if The vulnerable unserialize code executes during normal theme operation or when specific theme features are accessed
Your environment is affected if the Umberto theme version is unpatched and the theme processes untrusted serialized data through PHP's unserialize function.
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 dataUpdate Umberto theme to the latest patched version. If patching is not immediately possible, disable the theme or implement web application firewall rules to detect and block malicious serialized payloads.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-31423 — 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-2025-31423 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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- Version or environment caveats, and links to real fixes
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