Skip to main content

Subscribe to Comments EUVDEUVD-2026-96793

| CVE-2026-91829 HIGH
Cross-site Scripting (XSS) (CWE-79)
2026-10-11 WPScan GHSA-prwf-5jq7-v6fg
7.1
CVSS 3.1 · Vendor: WPScan
View

Attack ChainAIDerived

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

  1. Access
    Craft malicious URL with XSS payload
  2. Delivery
    Deliver link to victim via phishing/comment
  3. Exploit
    Victim (e.g. admin) clicks link
  4. Execution
    Payload reflected into link target
  5. Persist
    Script executes in victim browser
  6. Impact
    Steal session or act as admin

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 that a victim click an attacker-crafted URL targeting the Subscribe to Comments plugin (versions before 2.3.3), where a specific parameter is reflected unvalidated into a link target; per the CVSS vector (PR:N) no authentication is needed by the attacker. The key LIMITING factor is mandatory user interaction (UI:R) - the attack does not fire automatically and depends on social-engineering a user, ideally a logged-in administrator, into following the malicious link. Impact is also bounded to a single victim's browser session per click (reflected, not stored). No special server configuration is cited as a prerequisite in the description, but the vulnerable plugin must be installed and active and the target below 2.3.3.

Impact

Signals are largely consistent and point to a moderate, user-interaction-gated web vulnerability rather than a top-tier emergency. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L, base 7.1 High) shows a network-reachable, low-complexity, unauthenticated flaw, but the required UI:R (victim must click a crafted URL) and the limited (Low) impact to confidentiality/integrity/availability temper the real-world severity - this is characteristic of reflected XSS, not a wormable RCE. Public exploit code exists (WPScan), which raises the practical likelihood of opportunistic use, but there is NO CISA KEV listing and NO EPSS score was provided in the input, so I cannot quantify exploitation probability; the absence of EPSS/KEV should not be read as 'safe,' only as 'unconfirmed widespread exploitation.' No SSVC decision data (exploitation/automatable/technical-impact) was supplied. Net assessment: a credible, prioritize-for-patching issue - especially because successful exploitation can target administrators who click a malicious link - but it is not a drop-everything mass-exploitation threat given the user-interaction requirement and Low impact metrics.

Exploit ScenarioDerived

An attacker crafts a malicious URL for the vulnerable plugin where an unvalidated parameter is reflected into a link target, then delivers it to a victim (e.g., a WordPress administrator) via phishing, a comment, or a planted link. When the victim clicks, attacker-controlled script executes in their browser in the site's context, enabling session/cookie theft or actions on the victim's behalf. Public exploit details are available from WPScan, lowering the effort required to reproduce the attack.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.2% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Oct 11, 2026

Reflected cross-site scripting in the Subscribe to Comments WordPress plugin (all versions before 2.3.3) allows remote attackers to inject script through a crafted URL whose parameter is reflected unvalidated into a link target, executing in the browser of anyone who clicks it, including logged-in administrators. Per the assessed CVSS vector (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) the attacker needs no authentication (PR:N), but exploitation is gated by mandatory user interaction (UI:R) and is confined to a single victim's browser session per click - it is reflected, not stored, and does not compromise the server. Publicly available exploit code exists, the vendor has released a patched version (2.3.3), and the issue is not listed in CISA KEV, so confirmed active exploitation is not established; risk is moderate and user-interaction-gated rather than an emergency.

RemediationAI

Apply the vendor-released patch by upgrading the Subscribe to Comments WordPress plugin to version 2.3.3 or later, available through the WordPress.org plugin repository or at the advisory https://wpscan.com/vulnerability/1ed0314d-9871-4914-bb9c-ff894ea4c400/; this is the only complete fix because the flaw is a missing validation/encoding step in the plugin's own link-generation code. If the upgrade cannot be staged immediately, the most reliable compensating control is to deactivate the plugin until patching is possible - the trade-off is that comment-subscription and notification functionality is lost, which is usually acceptable given the plugin is rarely business-critical. A WAF or reverse-proxy rule that inspects query strings for script-scheme or attribute-breakout patterns on requests to the plugin's endpoints offers interim virtual patching, but it must be tuned to avoid false positives on legitimate comment-subscription links and is only a stopgap that can be bypassed by encoding variations. Because exploitation is reflected and requires a click, restricting administrator browsing of untrusted links reduces exposure but is not a technical control and should not be relied upon; no server configuration change or authentication requirement on the endpoint removes the vulnerability. Verify the deployed plugin version after upgrading and re-scan to confirm the reflection point no longer accepts unvalidated input.

Affected VersionsENISA

Subscribe to Comments 0 <2.3.3

Affected Packages

euvd subscribe_to_comments fix: 2.3.3

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 vulnerable component is a WordPress plugin written in PHP, and the root cause falls under CWE-79 (Improper Neutralization of Input During Web Page Generation, i.e. cross-site scripting). A request parameter is taken from the incoming URL and echoed into the target of a link (an href/URL attribute) without validation or output encoding, so an attacker can supply a payload that either uses a script-bearing scheme such as javascript: or breaks out of the attribute context to inject markup. Because the vulnerable page is served by the WordPress site, the injected script runs in the origin of the target site, and the CVSS scope change (S:C) reflects that the vulnerable PHP component is not the component ultimately affected - the victim's browser session is. The vector's PR:N means the attacker does not need an account on the WordPress site; UI:R means the victim must be induced to follow the crafted URL, which is why administrators are the highest-value target given the privileges a successful session hijack or CSRF-style action could reach. The CPE record cpe:2.3:a:unknown:subscribe_to_comments:*:*:*:*:*:*:*:* lists the plugin under an unenumerated vendor with a wildcard version, so version scoping should be taken from the EUVD range rather than from the CPE; EUVD places affected releases in the range 0 < 2.3.3.

Know when Subscribe To Comments gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

Vendor (WPScan) PRIMARY 7.1 HIGH
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
vuln.today AI 6.1 MEDIUM

Unauthenticated network-delivered reflected XSS requiring a victim click (PR:N, UI:R); script runs in the victim browser context (S:C) with Low C/I and no availability impact.

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

Primary rating from Vendor (WPScan).

CVSS VectorVendor: WPScan

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

Lifecycle Timeline

4
CVSS changed
Oct 11, 2026 - 12:22 NVD
7.1 (HIGH)
Patch available
Oct 11, 2026 - 08:01 EUVD
CVE Published
Oct 11, 2026 - 06:00 cve.org
UNKNOWN (no severity yet)
CVE Published
Oct 11, 2026 - 06:00 cve.org
HIGH 7.1

DescriptionCVE.org

The Subscribe to Comments WordPress plugin before 2.3.3 does not properly validate a parameter before reflecting it into a link target, allowing unauthenticated attackers to perform Reflected Cross-Site Scripting via a crafted URL against anyone who clicks it, including administrators.

Technical POC Analysis

Reflected cross-site scripting (CWE-79) in the WordPress plugin subscribe-to-comments (Subscribe to Comments).

Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.

Executive ViewAI

Why It Matters

The Subscribe to Comments WordPress plugin, present in all versions before 2.3.3 on our internet-facing WordPress properties, contains a reflected cross-site scripting flaw that runs attacker-supplied script in the browser of anyone who clicks a crafted link - including logged-in administrators. Exploitation is click-gated and confined to the individual victim's browser session rather than the web server, so the exposure is contained, but a hijacked administrator session could expose site administration functions on the affected property. Leadership should care because publicly available exploit code lowers the barrier for opportunistic attackers targeting a public publishing platform, even though risk remains moderate rather than urgent.

Business Impact: Medium
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.2%
Top 94% exploitable
Prevalence
Medium
established but niche WordPress comment-subscription plugin, not universally deployed
Exploit
POC
Public exploit code exists
Social Media
1
Sightings
Data Quality
6 sources
Confidence: High

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 HIGH
CISA KEV No
Public POC Yes
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
Medium
Technical Impact
Partial

Priority Score

56
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: +20
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.

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy