CVE-2026-40758
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 Léonie <= 1.2.1 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 · high confidenceUnauthenticated PHP Object Injection in Léonie CMS versions 1.2.1 and below allows remote attackers to inject malicious PHP objects into the application without authentication. This type of vulnerability occurs when unserialized data from untrusted sources is processed, potentially enabling remote code execution depending on available gadget chains.
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 installed Léonie CMS versionLocate the version file (often version.php, composer.json, or a VERSION file in the root directory) and read its contents. Alternatively, check the admin dashboard About page if accessible.Affected if The version is 1.2.1 or lower.
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Locate PHP deserialization usageSearch the source code for calls to unserialize() function. In the application root, run: grep -r "unserialize" --include="*.php" .Affected if Any PHP file contains unserialize() processing data from $_GET, $_POST, $_COOKIE, or similar user-controlled sources.
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Identify deserialization entry pointsExamine each file containing unserialize() calls. Look for where the data being deserialized originates (e.g., $_REQUEST['data'], $_COOKIE['token'], etc.).Affected if User-supplied input (request parameters, cookies, headers) flows directly into unserialize() without validation.
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Check authentication requirements for the entry pointReview the PHP files handling deserialized data to determine if they perform any authentication or access control checks before calling unserialize().Affected if The deserialization occurs in code paths accessible to unauthenticated users (no login required).
You are affected if Léonie CMS version is 1.2.1 or lower AND the application uses unserialize() on unauthenticated user input without prior validation.
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 to a patched version of Léonie if available; otherwise, implement strict input validation and replace PHP unserialize() with safer alternatives such as JSON parsing for user-controlled data.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-40758 — 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-2026-40758 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
- No spam, self-promotion, credentials, or personal data