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Full vulnerability report · 2026
CVE-2026-15985High confidence

Classified Listing - Mobile Number Verification <= 1.6.0 - Unauthenticated Authentication Bypass via Firebase OTP Login

RadiusTheme · Classified Listing - Mobile Number Verification

8.1HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-66410

No EUVD known-exploited evidence

The Classified Listing - Mobile Number Verification plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.6.0. This is due to missing server-side Firebase OTP validation in the process_otp_login() function. This makes it possible for unauthenticated attackers to authenticate as any user with a phone number registered in the plugin's phone table by submitting an arbitrary OTP code and UID through the Firebase OTP login flow. Successful exploitation requires OTP login to be enabled with Firebase selected as the verification gateway, and requires the attacker to know or guess the target account's registered phone number. Administrator account takeover is possible if an administrator account has a phone number registered in the plugin.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
8.1 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

The Classified Listing - Mobile Number Verification plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.6.0. This is due to missing server-side Firebase OTP validation in the process_otp_login() function. This makes it possible for unauthenticated attackers to authenticate as any user with a phone number registered in the plugin's phone table by submitting an arbitrary OTP code and UID through the Firebase OTP login flow. Successful exploitation requires OTP login to be enabled with Firebase selected as the verification gateway, and requires the attacker to know or guess the target account's registered phone number. Administrator account takeover is possible if an administrator account has a phone number registered in the plugin.

What

The Classified Listing - Mobile Number Verification plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.6.0. This is due to missing server-side Firebase OTP validation in the process_otp_login() function. This makes it possible for unauthenticated attackers to authenticate as any user with a phone number registered in the plugin's phone table by submitting an arbitrary OTP code and UID through the Firebase OTP login flow. Successful exploitation requires OTP login to be enabled with Firebase selected as the verification gateway, and requires the attacker to know or guess the target account's registered phone number. Administrator account takeover is possible if an administrator account has a phone number registered in the plugin.

Why

The product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may bypass an access boundary or take over an account.

What

The Classified Listing - Mobile Number Verification plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.6.0. This is due to missing server-side Firebase OTP validation in the process_otp_login() function. This makes it possible for unauthenticated attackers to authenticate as any user with a phone number registered in the plugin's phone table by submitting an arbitrary OTP code and UID through the Firebase OTP login flow. Successful exploitation requires OTP login to be enabled with Firebase selected as the verification gateway, and requires the attacker to know or guess the target account's registered phone number. Administrator account takeover is possible if an administrator account has a phone number registered in the plugin.

Why

The product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may bypass an access boundary or take over an account.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Authentication Bypass by Alternate Name → bypass an access boundary or take over an account
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-289 ↗

CWE-289: Authentication Bypass by Alternate Name. The product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkUnauthenticatedCWE-289
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-66410Official EUVD mapping

The Classified Listing - Mobile Number Verification plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.6.0. This is due to missing server-side Firebase OTP validation in the process_otp_login() function. This makes it possible for unauthenticated attackers to authenticate as any user with a phone number registered in the plugin's phone table by submitting an arbitrary OTP code and UID through the Firebase OTP login flow. Successful exploitation requires OTP login to be enabled with Firebase selected as the verification gateway, and requires the attacker to know or guess the target account's registered phone number. Administrator account takeover is possible if an administrator account has a phone number registered in the plugin.

Official EUVD record
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
≤ 1.6.0
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 26 Aug 2026 · Last source change 26 Aug 2026, 12:30 UTC · CWE-289 · Authentication Bypass by Alternate Name

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-27
European sourceENISA EUVD · EUVD-2026-66410
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →
  1. ENISA EUVD mappingEUVD-2026-66410 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-66410"}
    ENISA EUVD ↗
  2. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-66410↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-15985 · cve.blacktree.nl