CVE-2026-15981

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-23. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0

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

The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP's openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error — bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
59(Track)
EG Risk 59/100SSVC: 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%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
43%
KEV
Not listed

Published

July 23, 2026

Last Modified

July 24, 2026

References (7)

Vendor Advisories for CVE-2026-15981(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 44× in last 7d / 46× 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. 2026-07-31 10:01 UTCGHSA enrichment
  2. 2026-07-31 05:46 UTCGHSA enrichment
  3. 2026-07-31 01:31 UTCGHSA enrichment
  4. 2026-07-30 21:13 UTCGHSA enrichment
  5. 2026-07-30 16:59 UTCEG score recompute
  6. 2026-07-30 16:59 UTCGHSA enrichment
  7. 2026-07-30 12:27 UTCEG score recompute
  8. 2026-07-30 12:27 UTCGHSA enrichment
  9. 2026-07-30 08:12 UTCGHSA enrichment
  10. 2026-07-30 03:58 UTCEG score recompute
  11. 2026-07-30 03:58 UTCGHSA enrichment
  12. 2026-07-30 01:30 UTCEPSS rescore
  13. 2026-07-29 23:43 UTCGHSA enrichment
  14. 2026-07-29 19:29 UTCGHSA enrichment
  15. 2026-07-29 15:12 UTCGHSA enrichment
  16. 2026-07-29 10:57 UTCGHSA enrichment
  17. 2026-07-29 06:42 UTCGHSA enrichment
  18. 2026-07-29 02:26 UTCGHSA enrichment
  19. 2026-07-28 22:11 UTCGHSA enrichment
  20. 2026-07-28 17:19 UTCEG score recompute
  21. 2026-07-28 17:19 UTCGHSA enrichment
  22. 2026-07-28 13:05 UTCGHSA enrichment
  23. 2026-07-28 08:49 UTCGHSA enrichment
  24. 2026-07-28 04:33 UTCGHSA enrichment
  25. 2026-07-28 00:18 UTCGHSA enrichment
Show 21 more
  1. 2026-07-27 19:46 UTCGHSA enrichment
  2. 2026-07-27 15:29 UTCEG score recompute
  3. 2026-07-27 15:29 UTCGHSA enrichment
  4. 2026-07-27 14:13 UTCEPSS rescore
  5. 2026-07-27 11:14 UTCGHSA enrichment
  6. 2026-07-27 07:00 UTCGHSA enrichment
  7. 2026-07-27 02:44 UTCGHSA enrichment
  8. 2026-07-26 22:29 UTCGHSA enrichment
  9. 2026-07-26 18:15 UTCEG score recompute
  10. 2026-07-26 18:14 UTCGHSA enrichment
  11. 2026-07-26 14:54 UTCEPSS rescore
  12. 2026-07-26 14:54 UTCEPSS rescore
  13. 2026-07-26 13:58 UTCEG score recompute
  14. 2026-07-26 13:58 UTCGHSA enrichment
  15. 2026-07-26 09:44 UTCGHSA enrichment
  16. 2026-07-26 03:06 UTCEG score recompute
  17. 2026-07-26 03:06 UTCGHSA enrichment
  18. 2026-07-25 14:17 UTCEPSS rescore
  19. 2026-07-24 14:17 UTCEPSS rescore
  20. 2026-07-23 20:47 UTCEG score recompute
  21. 2026-07-23 20:46 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-15981?
CVE-2026-15981 is a critical vulnerability published on July 23, 2026. The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mosamlvalidatesignature() function performing a loose boolean check on the raw tri-state integer returned by PHP's opensslverify(), causing…
When was CVE-2026-15981 disclosed?
CVE-2026-15981 was first published in the National Vulnerability Database on July 23, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-15981 actively exploited?
CVE-2026-15981 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 57.3% of all scored CVEs.
What is the CVSS score of CVE-2026-15981?
CVE-2026-15981 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-15981?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-15981, 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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