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CVE Record

CVE-2026-15407: Themify Builder <= 7.7.7 - Missing Authorization to Authenticated (Subscriber+) Arbitrary Post Stylesheet Write/Delete via tb_generate_on_fly AJAX Action

The Themify Builder plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 7.7.7. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for authenticated attackers, with subscriber-level access and above, to overwrite or delete the generated CSS stylesheet file of arbitrary posts, including private and draft posts owned by other users, and modify plugin-scoped font options. The required CSRF nonce (tf_nonce) is emitted on public front-end builder pages via wp_localize_script, making it trivially obtainable by any authenticated user visiting such a page.

MediumCVSS 4.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A logged-in WordPress user with Subscriber or higher privileges can make Themify Builder overwrite or delete generated CSS files for arbitrary posts, including private or draft content owned by others. The impact appears limited to styling and plugin-scoped font options, but it can disrupt page presentation and affect content integrity on sites that allow low-privilege accounts.

Executive priority

Treat this as a moderate-priority WordPress integrity issue. It is not described as data theft or full site compromise, but sites with many low-privilege users should move quickly because the prerequisite account level is common and the nonce exposure lowers practical barriers.

Technical view

Themify Builder through 7.7.7 lacks authorization checks around the tb_generate_on_fly AJAX action. Sources describe CWE-862, network-accessible, low-complexity exploitation requiring authenticated low-privilege access, with no confidentiality or availability impact in the CVSS vector and low integrity impact.

Likely exposure

Exposure is mainly WordPress sites running Themify Builder versions up to and including 7.7.7 where untrusted or broadly issued accounts have Subscriber or higher access. Public registration, customer portals, contributor programs, or compromised low-privilege accounts increase practical risk.

Exploitation context

The source bundle says the required tf_nonce is emitted on public front-end builder pages and is obtainable by authenticated users. KEV is false, and the provided sources do not state active exploitation in the wild.

Researcher notes

Focus validation on authorization around tb_generate_on_fly and generated stylesheet operations. The provided code references identify Themify Builder stylesheet handling across 7.7.5 and 7.7.7 plus a WordPress Trac changeset, but the bundle does not provide proof of active exploitation.

Mitigation direction

  • Update Themify Builder according to vendor or WordPress plugin guidance when a fixed release is available.
  • Restrict Subscriber-level accounts to trusted users until remediation is confirmed.
  • Disable public user registration if it is not business-critical.
  • Review and restore unexpected generated CSS changes for important posts.
  • Monitor Wordfence, CVE, and WordPress plugin sources for fix confirmation.

Validation and detection

  • Inventory WordPress sites using Themify Builder.
  • Confirm installed Themify Builder versions are not 7.7.7 or earlier.
  • Review whether untrusted users can authenticate with Subscriber or higher roles.
  • Check logs for unusual AJAX activity involving tb_generate_on_fly.
  • Inspect sensitive pages for unexpected styling or font-option changes.
Prepared
Confidence
high
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-862: Authorization and privilege behavior lookup

Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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

Privilege behavior lookup

The CVE wording references privilege impact, so privilege escalation and authorization behavior 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-2026-15407 mapping review

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

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.3 (3.1)
Known Exploited
No
Published

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

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
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

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
4.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N2.81.4Wordfence

Vulnerability scoring details

Base CVSS 3.1 score

4.3Medium
CVSS 3.1 vector shape for CVE-2026-15407Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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
themifymeThemify Builder0unaffected
Weakness

CWE details

CWE-862

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

CWE-862 · source CWE mapping

Missing Authorization

Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs