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CVE Record

CVE-2026-15748: Forminator Forms <= 1.56.1 - Unauthenticated Arbitrary File Upload via Forged Upload Field Configuration

The Forminator Forms plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 1.56.1 via the handle_file_upload function. This is due to insufficient file type validation in handle_file_upload, where the dangerous-extension blocklist performs exact-key matching that is bypassed by pipe-alternative MIME type keys, combined with a public submission handler that trusts attacker-controlled upload field configuration injected via a forged Select field value. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

An unauthenticated attacker can abuse public Forminator form handling to upload a potentially executable file. If the server executes that file, the attacker could take full control of the WordPress site, access sensitive data, alter content, or disrupt service.

Executive priority

Treat as an emergency remediation for internet-facing sites. Prioritize asset discovery, vendor-guided updating, and compromise review because successful exploitation could produce complete site takeover without credentials or user interaction.

Technical view

Forminator Forms through 1.56.1 inadequately validates uploaded file types. Exact-key blocklist matching can be bypassed using alternative MIME-type keys, while the public submission path trusts forged upload-field configuration supplied through a Select field value. This combination enables arbitrary file upload and may lead to remote code execution.

Likely exposure

Internet-facing WordPress sites running Forminator Forms 1.56.1 or earlier are potentially exposed, especially where public custom-form submission endpoints are reachable. The bundle does not establish whether particular server configurations will execute uploaded files.

Exploitation context

The CVSS 3.1 score is 9.8 because exploitation is remote, unauthenticated, low complexity, and requires no user interaction. The bundle marks KEV as false and provides no evidence of active exploitation or a public exploit.

Researcher notes

The supplied code references show relevant paths in version 1.55.1, while the CVE description states the affected boundary is through 1.56.1. No confirmed patched version or vendor mitigation is included. Researchers should distinguish successful upload from code execution, which depends on server handling.

Mitigation direction

  • Inventory internet-facing WordPress sites and identify installed Forminator versions.
  • Check current WPMU DEV or WordPress plugin guidance for the confirmed fixed release.
  • Update promptly to the vendor-confirmed fixed version when identified.
  • If immediate updating is impossible, disable Forminator or public form submissions where operationally acceptable.
  • Prevent uploaded content from executing through web-server and upload-directory controls.

Validation and detection

  • Confirm every Forminator installation and version across production, staging, and disaster-recovery environments.
  • Identify publicly reachable Forminator forms and submission endpoints.
  • Review web, application, and upload logs for unusual form submissions or file creation.
  • Inspect upload locations for unexpected or executable-capable files, preserving evidence before removal.
  • After remediation, verify public forms work and server controls prevent uploaded-file execution.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-434: File access and web shell behavior lookup

File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
description · low confidence lookup

File access behavior lookup

The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-15748 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
5Timeline events
1ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: total

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Wordfence

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2026-15748Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. Source timelineWordfence

    Vendor Notified

  3. Source timelineWordfence

    Disclosed

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
wpmudevForminator Forms – Contact Form, Payment Form & Custom Form Builder0unaffected
Weakness

CWE details

CWE-434

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-434 · source CWE mapping

Unrestricted Upload of File with Dangerous Type

Unrestricted Upload of File with Dangerous Type represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs