CVE-2026-15826

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-15. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this weekElevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 9.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
65(Track*)
EG Risk 65/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
2%
EPSS %ILE
83%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 20, 2026

References (9)

Vendor Advisories for CVE-2026-15826(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 55× in last 7d / 55× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-21 03:54 UTCGHSA enrichment
  2. 2026-08-21 00:12 UTCEG score recompute
  3. 2026-08-21 00:12 UTCGHSA enrichment
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-20 20:30 UTCGHSA enrichment
  6. 2026-08-20 16:47 UTCGHSA enrichment
  7. 2026-08-20 13:02 UTCGHSA enrichment
  8. 2026-08-20 09:14 UTCGHSA enrichment
  9. 2026-08-20 05:30 UTCGHSA enrichment
  10. 2026-08-20 01:47 UTCGHSA enrichment
  11. 2026-08-19 22:04 UTCGHSA enrichment
  12. 2026-08-19 18:22 UTCEG score recompute
  13. 2026-08-19 18:22 UTCGHSA enrichment
  14. 2026-08-19 17:03 UTCEPSS rescore
  15. 2026-08-19 13:10 UTCGHSA enrichment
  16. 2026-08-19 09:28 UTCGHSA enrichment
  17. 2026-08-19 05:45 UTCGHSA enrichment
  18. 2026-08-19 02:03 UTCGHSA enrichment
  19. 2026-08-18 22:21 UTCGHSA enrichment
  20. 2026-08-18 18:39 UTCGHSA enrichment
  21. 2026-08-18 14:57 UTCEG score recompute
  22. 2026-08-18 14:57 UTCGHSA enrichment
  23. 2026-08-18 13:48 UTCEPSS rescore
  24. 2026-08-18 11:04 UTCGHSA enrichment
  25. 2026-08-18 11:02 UTCGHSA enrichment
Show 30 more
  1. 2026-08-18 07:18 UTCGHSA enrichment
  2. 2026-08-18 03:36 UTCGHSA enrichment
  3. 2026-08-17 23:53 UTCGHSA enrichment
  4. 2026-08-17 20:10 UTCGHSA enrichment
  5. 2026-08-17 16:25 UTCGHSA enrichment
  6. 2026-08-17 14:52 UTCEG score recompute
  7. 2026-08-17 14:52 UTCGHSA enrichment
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-17 11:10 UTCGHSA enrichment
  10. 2026-08-17 07:28 UTCGHSA enrichment
  11. 2026-08-17 03:46 UTCGHSA enrichment
  12. 2026-08-17 00:04 UTCGHSA enrichment
  13. 2026-08-16 20:22 UTCGHSA enrichment
  14. 2026-08-16 16:40 UTCEG score recompute
  15. 2026-08-16 16:40 UTCGHSA enrichment
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 12:58 UTCGHSA enrichment
  18. 2026-08-16 09:15 UTCGHSA enrichment
  19. 2026-08-16 05:33 UTCEG score recompute
  20. 2026-08-16 05:33 UTCGHSA enrichment
  21. 2026-08-16 02:14 UTCEPSS rescore
  22. 2026-08-16 01:52 UTCGHSA enrichment
  23. 2026-08-15 22:10 UTCGHSA enrichment
  24. 2026-08-15 18:28 UTCGHSA enrichment
  25. 2026-08-15 14:46 UTCGHSA enrichment
  26. 2026-08-15 11:04 UTCEG score recompute
  27. 2026-08-15 11:04 UTCGHSA enrichment
  28. 2026-08-15 07:22 UTCEG score recompute
  29. 2026-08-15 06:58 UTCEG score recompute
  30. 2026-08-15 06:56 UTCMITRE cvelistV5first tracked

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2026/CVE-2026-15826.yaml
    First seen Jan 1, 2026

    User Profile Builder 3.16.4 - Unauthenticated Authentication Bypass

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-15826?
CVE-2026-15826 is a critical vulnerability published on August 15, 2026. 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 wppbloginuser() function calling absint() on the return value of wpinsertuser() before performing an iswperror() check — when a…
When was CVE-2026-15826 disclosed?
CVE-2026-15826 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-15826 actively exploited?
CVE-2026-15826 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 16.7% of all scored CVEs.
What is the CVSS score of CVE-2026-15826?
CVE-2026-15826 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-15826?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-15826, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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