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Meow Lightbox CVE-2026-107756

| EUVDEUVD-2026-100906 MEDIUM
Cross-site Scripting (XSS) (CWE-79)
2026-10-14 Wordfence GHSA-6wgq-mq9p-cpvg
6.4
CVSS 3.1 · Vendor: Wordfence
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain subscriber account with one approved comment
  2. Delivery
    Submit comment with crafted display_name/body payload
  3. Exploit
    Payload stored unsanitized via Output Buffering
  4. Execution
    Admin or visitor loads injected page
  5. Impact
    Script executes in victim browser session

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires THREE concrete conditions, all drawn from the description: (1) an authenticated account at subscriber level or above (CVSS PR:L); (2) the plugin's 'Output Buffering' option must be explicitly enabled - it is DISABLED by default, so default installations are not exploitable; and (3) the attacker must already have at least one previously approved comment on the site, which causes WordPress core to auto-approve their subsequent malicious comment carrying the payload in the 'display_name + comment' parameter. Limiting factors that reduce realistic risk: the non-default Output Buffering requirement, the need for a prior approved comment, and the requirement for any authenticated account (sites without open registration raise the bar further). Payload execution occurs when a user/admin views the injected page.

Impact

This is a moderate-severity Stored XSS (CVSS 6.4, CWE-79) whose real-world risk is substantially lower than the headline score suggests because of stacked preconditions. The input CVSS vector (AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N) treats the attack as low-complexity, but the description explicitly imposes two non-trivial gates that argue for higher complexity: the plugin's 'Output Buffering' option must be enabled (it is disabled by default), and the attacker must already have at least one previously approved comment so that WordPress core auto-approves subsequent (malicious) comments. There is no EPSS score, no CISA KEV listing, and no public exploit code in the provided data, so the exploitation status is 'no public exploit identified at time of analysis' - no SSVC/automatable signals were supplied either. The CVSS vector contains PR:L, so exploitation requires an authenticated account at subscriber level or above, which is often trivially obtainable on sites with open registration but still a barrier versus a fully unauthenticated flaw. Net assessment: a genuine but conditional, low-urgency issue for most deployments - prioritize patching only where open user registration, approved commenters, and the non-default Output Buffering setting coincide. No key signals conflict, but note the input vector's AC:L understates the real-world non-default-configuration and prior-approved-comment requirements.

Exploit ScenarioDerived

On a site that has enabled Meow Lightbox's non-default Output Buffering option, an attacker registers a subscriber account (or uses any account with an already-approved comment) and submits a comment whose display name and body carry a malicious script payload; because the author has a prior approved comment, WordPress auto-approves it. When an administrator or other visitor later views the page, the stored script executes in their browser session. No public proof-of-concept was provided in the intelligence sources.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 14, 2026

Stored cross-site scripting in the Meow Lightbox WordPress plugin (all versions up to and including 5.6.2) allows an authenticated subscriber-level user to inject arbitrary script through the 'display_name + comment' parameter, which then executes in the browser of any user viewing the injected page. Real-world risk is substantially lower than the 6.4 headline score suggests because three preconditions must all be met: the plugin's Output Buffering option must be explicitly enabled (it is disabled by default), the attacker must already have at least one approved comment on the site so that WordPress core auto-approves subsequent submissions, and any authenticated account (PR:L) is required - making default installations non-exploitable. No public exploit code or confirmed active exploitation has been identified at time of analysis, and no EPSS or CISA KEV signal is present in the available intelligence.

RemediationAI

Upgrade Meow Lightbox to a version later than 5.6.2: the tracked fix appears in the plugin's Trac changeset 3737480 (https://plugins.trac.wordpress.org/changeset/3737480/meow-lightbox), which updates the vendored php-simple-html-dom-parser and core output handling - treat this as an upstream fix available via commit/changeset, with a released patched version not independently confirmed, so verify the installed version banner after updating and re-check the plugin repository for the tagged release. Until confirmed-patched code is deployed, the most effective compensating control is to leave the plugin's Output Buffering option disabled, since the injected payload only reaches rendered output through that buffered path; the trade-off is the loss of whatever markup/lightbox post-processing the option provides. Additionally, tight comment moderation reduces exposure: require manual approval for all comments (or restrict comment privileges to trusted roles) so an attacker cannot leverage a prior approved comment to get payloads auto-approved, at the cost of moderator workload. Limiting or disabling open subscriber self-registration removes the low-privilege foothold the attack requires. Finally, apply a web application firewall rule or content-security-policy that blocks inline script execution in comment-derived output as defense in depth. Note that WordPress core alone cannot fix this - the flaw resides in the plugin's buffering and DOM-parsing pipeline, so patching the plugin is the only complete remedy.

Affected VersionsENISA

Meow Lightbox 0 ≤5.6.2

Affected Packages

euvd meow_lightbox no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause is CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically a stored cross-site scripting flaw in the tigroumeow:meow_lightbox WordPress plugin (CPE cpe:2.3:a:tigroumeow:meow_lightbox:*:*:*:*:*:*:*:*). Meow Lightbox renders comment-related content and, when its optional Output Buffering feature is enabled, buffers page output and post-processes it through a vendored copy of the kub-at/php-simple-html-dom-parser library (references point at simple_html_dom.php lines in the 5.6.2 tag, plus core.php lines handling output handling and comment processing). Because the 'display_name + comment' values are not adequately sanitized on input nor escaped on output before being written into the buffered HTML, an attacker-controlled string survives into rendered pages as executable markup. The vulnerability therefore only manifests against the buffered output path, not the default rendering path. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N (6.4) reflects a network-reachable, low-privilege, no-user-interaction, scope-changing XSS; an independent assessment raises attack complexity to High (AC:H) to account for the stacked non-default prerequisites, which is the more realistic characterization. The attack chain also depends on WordPress core's own comment-approval behavior: a pre-existing approved comment from the same identity causes later submissions to be auto-approved, which is what lets the payload persist without moderator review.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (Wordfence) PRIMARY 6.4 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
vuln.today AI 4.9 MEDIUM

Network stored XSS executing in other users' browsers (S:C, C:L/I:L); AC:H because it needs non-default Output Buffering plus a pre-approved comment, and PR:L for subscriber authentication.

3.1 AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N
4.0 AV:N/AC:H/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Primary rating from Vendor (Wordfence).

CVSS VectorVendor: Wordfence

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionCVE.org

The Meow Lightbox plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'display_name + comment' parameter in all versions up to, and including, 5.6.2 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This vulnerability is only exploitable when the plugin's Output Buffering option is enabled (disabled by default), and requires the attacker to have at least one previously approved comment on the site so that subsequent comments are auto-approved by WordPress core.

Threat Intelligence Overview

EPSS Score
0.3%
Top 77% exploitable
Prevalence
Low
niche WordPress image-lightbox plugin with modest install base
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

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