CVE-2026-42879
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 · uneditedFacturaScripts is an open source accounting and invoicing software. In 2025.81 and earlier, an authenticated unrestricted file upload vulnerability exists in FacturaScripts' product image upload functionality. An attacker with valid credentials can upload a PHP file disguised as a GIF image (using a GIF89a header), bypassing MIME type validation. The file is stored with its original extension, including executable extensions such as .php. The vulnerability exists the addImageAction() method of Core/Lib/ExtendedController/ProductImagesTrait.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 · high confidenceAuthenticated unrestricted file upload in FacturaScripts allows users to upload PHP files disguised as images by adding a GIF89a header while preserving the .php extension. The addImageAction() method in ProductImagesTrait.php validates MIME type but not actual file content or extension, enabling remote code execution.
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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
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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Confirm FacturaScripts installation and versionLocate FacturaScripts in your environment and identify its version by checking version files, composer.json, or admin panel informationAffected if FacturaScripts is installed and the version matches or precedes the vulnerable release cycle containing ProductImagesTrait.php with addImageAction()
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Locate the ProductImagesTrait.php fileSearch for ProductImagesTrait.php in the FacturaScripts installation directory and verify the addImageAction() method existsAffected if The file exists and contains the addImageAction() method that handles image uploads
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Verify image upload feature is accessible to authenticated usersCheck if authenticated users have access to product image upload functionality through the admin panel or API endpointAffected if Authenticated users can access and use the product image upload feature
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Inspect upload directory configuration and locationExamine the configuration to determine where uploaded files are stored and whether the storage path is within the webrootAffected if Uploaded files are stored in a web-accessible directory without proper access restrictions
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Scan upload directories for suspicious PHP filesList files in upload directories and check for any .php files or files containing PHP code, especially those with GIF89a headersAffected if Any .php files exist in upload directories or files with .php extension are found in web-accessible paths
You are affected if FacturaScripts with the vulnerable addImageAction() method is running, authenticated users can access the image upload feature, and PHP files with executable extensions are present in web-accessible upload directories.
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 dataImplement content-based validation using magic byte checking, rename uploaded files to non-executable names with safe extensions, and store uploads outside the webroot or with proper access controls.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42879 — 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-2026-42879 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