CVE-2026-1555
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 · uneditedThe WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
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 confidenceThe WebStack WordPress theme lacks file type validation in its io_img_upload() function, allowing unauthenticated attackers to upload arbitrary files to the server. This unrestricted file upload capability can be leveraged to achieve 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
- 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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Confirm WebStack theme is installedNavigate to WordPress dashboard > Appearance > Themes, or inspect /wp-content/themes/ directory for a theme named 'WebStack' or similarAffected if The WebStack theme is active on the WordPress installation
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Locate theme version informationCheck the theme's style.css header for the Version field, or inspect the main theme PHP file for a version constantAffected if The installed version cannot be verified as patched, or no version information is found
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Identify the io_img_upload functionSearch theme files (especially in includes/ or lib/ directories) for the string 'io_img_upload' using grep or a file search toolAffected if The function io_img_upload() exists in the theme codebase and is accessible
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Verify file upload endpoint accessibilityInspect theme files for form handlers or AJAX actions that call io_img_upload, and check if they require authentication (look for 'is_user_logged_in' or similar checks)Affected if The upload functionality is reachable without authentication (no login requirement found)
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Test for missing file type validationReview the io_img_upload function code for MIME type checks, file extension allowlists, or validation routines before file processingAffected if No file type or extension validation is performed before the file is saved
A user is affected if the WebStack theme is installed, contains the io_img_upload function, and that function can be accessed without authentication and lacks file type 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 dataUpdate the WebStack theme to a patched version once available, or disable the io_img_upload() function and implement server-side file upload restrictions with strict allowlist validation.
- Consultation2.0 h
- Implementation4.0 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 $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-1555 — 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-2026-1555 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
- No spam, self-promotion, credentials, or personal data