CVE-2026-75957

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-10-01. 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 week
9.8EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 9.8Exploit: None knownExposed services: Not assessed

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

The Ultimate Multisite – WordPress Multisite SaaS & WaaS Platform plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 2.15.0 via the checkout_form parameter of the login_customer_after_checkout function. This is due to the publicly accessible wu_ajax_nopriv_wu_validate_form AJAX handler accepting a freely obtainable checkout nonce, and the checkout_form=wu-finish-checkout parameter causing get_validation_rules() to discard all validation rules while finish_checkout_form_fields() returns an empty step list — forcing is_last_step() to return true and routing the request directly into full order processing — after which maybe_create_customer() resolves the attacker-supplied email_address to an existing WordPress user ID without any authentication or ownership verification, and login_customer_after_checkout() calls wp_set_auth_cookie() for that user ID via a passwordless code path. This makes it possible for unauthenticated attackers to log in as any existing WordPress user — including a Network Super Admin — simply by knowing their email address. Exploitation requires that the targeted user account has no pre-existing Ultimate Multisite customer record; accounts such as a Network Super Admin on a fresh Multisite install, or any administrator or editor added before Ultimate Multisite was configured, satisfy this condition and are therefore exploitable.

CVSS v3
9.8
EG Score
9.8CRITICALhigh confidence
EG Risk
59
EG Risk 59/100CISA SSVC

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%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.6%
EPSS %ILE
45th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 1, 2026

Last Modified

October 1, 2026

References (13)

Vendor Advisories for CVE-2026-75957(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 31× in last 7d / 31× 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. 2026-10-04 11:04 UTCGHSA enrichment
  2. 2026-10-04 07:16 UTCGHSA enrichment
  3. 2026-10-04 03:27 UTCGHSA enrichment
  4. 2026-10-03 23:38 UTCGHSA enrichment
  5. 2026-10-03 19:49 UTCGHSA enrichment
  6. 2026-10-03 16:01 UTCEG score recompute
  7. 2026-10-03 16:01 UTCGHSA enrichment
  8. 2026-10-03 14:26 UTCEPSS rescore
  9. 2026-10-03 12:11 UTCGHSA enrichment
  10. 2026-10-03 08:22 UTCGHSA enrichment
  11. 2026-10-03 04:32 UTCGHSA enrichment
  12. 2026-10-03 00:44 UTCGHSA enrichment
  13. 2026-10-02 20:56 UTCEG score recompute
  14. 2026-10-02 20:56 UTCGHSA enrichment
  15. 2026-10-02 17:07 UTCGHSA enrichment
  16. 2026-10-02 13:19 UTCGHSA enrichment
  17. 2026-10-02 09:31 UTCGHSA enrichment
  18. 2026-10-02 05:42 UTCGHSA enrichment
  19. 2026-10-02 01:54 UTCGHSA enrichment
  20. 2026-10-01 22:05 UTCGHSA enrichment
  21. 2026-10-01 18:12 UTCGHSA enrichment
  22. 2026-10-01 14:21 UTCEG score recompute
  23. 2026-10-01 14:21 UTCGHSA enrichment
  24. 2026-10-01 13:56 UTCEG score recompute
  25. 2026-10-01 13:56 UTCGHSA enrichment
Show 6 more
  1. 2026-10-01 12:49 UTCGHSA enrichment
  2. 2026-10-01 12:10 UTCEG score recompute
  3. 2026-10-01 12:10 UTCGHSA enrichment
  4. 2026-10-01 08:22 UTCEG score recompute
  5. 2026-10-01 07:56 UTCEG score recompute
  6. 2026-10-01 07:55 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-75957?
CVE-2026-75957 is a critical vulnerability published on October 1, 2026. The Ultimate Multisite – WordPress Multisite SaaS & WaaS Platform plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 2.15.0 via the checkoutform parameter of the logincustomeraftercheckout function. This is due to the publicly accessible…
When was CVE-2026-75957 disclosed?
CVE-2026-75957 was first published on October 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-75957 actively exploited?
CVE-2026-75957 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (45th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-75957?
CVE-2026-75957 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-75957?
No fix for CVE-2026-75957 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-75957 are linked in the Vendor Advisories panel on this page.

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