Skip to content
Noroxi
NVD / CVE Program· CNA Wordfence

CVE-2026-15826: User Profile Builder <= 3.16.4 - Unauthenticated Authentication Bypass via Type Confusion to Administrator Account Takeover via 'username' Parameter

Noroxi assessment

Priority: Plan (action score 40/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 3.9% (FIRST EPSS); higher than 90.3% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • No fixed version is recorded, but the references include a patch (commit or PR) link.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Add it to your regular patch cycle. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The User Profile Builder plugin for WordPress is vulnerable to Authentication Bypass via Type Confusion in versions up to, and including, 3.16.4. This is due to the wppb_log_in_user() function calling absint() on the return value of wp_insert_user() before performing an is_wp_error() check — when a registration is submitted with a 61–70 character username, WordPress core rejects it with a WP_Error object, but absint() coerces that object to the integer 1 before the error check can short-circuit execution, causing the plugin to bind and return a transient-backed autologin nonce tied to user ID 1. This makes it possible for unauthenticated attackers to log in as the site's Administrator account (user ID 1), resulting in full administrative takeover of the site.

CriticalCVSS 9.8 · v3.1—Proof of concept No fix recorded
Published
Aug 15, 2026
Updated
Aug 20, 2026
EPSS
3.9% · 90th percentile

Report tools

JSON

Action score

40

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 3.9%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Wordfence
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Is User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor on your site?

WP Lens reads your site's plugin, theme and WordPress versions from the outside and matches them to known vulnerabilities. Works without an account.

Follow CVE-2026-15826

Is User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor on your site?

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for cozmoslabs records
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Wordfence). Independent of NVD's CPE analysis and usually ahead of it.

  • cozmoslabs User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor

    • up to and including 3.16.4affected · semver

Same product

cozmoslabs: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-109447User Profile Builder <= 4.0.3 - Unauthenticated Privilege Escalation to 'role' Parameter via Legacy Meta-Name Collision on [wppb-register]
    32Monitor
  • CVE-2026-115807User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor <= 4.0.3 - Authenticated (Author+) Limited Privilege Escalation via G
    28Monitor
  • CVE-2026-100186User Profile Builder <= 4.0.3 - Unauthenticated Stored Cross-Site Scripting via First Name Field
    28Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-13054Nov 19, 2025 · User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor <= 3.14.8 - Authenticated (Contributor+) Stored Cross-Site Scripting
    25Monitor
  • ← EarlierCVE-2026-3139Mar 31, 2026 · User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor <= 3.15.5 - Insecure Direct Object Reference to Authenticated (Subscr
    17Monitor
  • Later →CVE-2026-75965Sep 1, 2026 · User Profile Builder <= 4.0.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'date' Shortcode Attribute
    25Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2026-15826 —
Proof-of-concept repository on GitHubstars:02026-08-17

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+2 d
  3. TodayNov 9, 2026+86 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-704 · Incorrect Type Conversion or Cast

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (8 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records