CVE-2026-15981

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM 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(medium)
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
55%
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 34× in last 7d / 153× 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.

Showing the most recent 100 of 325 total refreshes for this CVE.

  1. 2026-09-15 09:50 UTCEG score recompute
  2. 2026-09-15 09:50 UTCGHSA enrichment
  3. 2026-09-14 16:12 UTCGHSA enrichment
  4. 2026-09-14 11:06 UTCGHSA enrichment
  5. 2026-09-14 06:52 UTCGHSA enrichment
  6. 2026-09-14 02:38 UTCGHSA enrichment
  7. 2026-09-13 22:22 UTCGHSA enrichment
  8. 2026-09-13 17:10 UTCEG score recompute
  9. 2026-09-13 17:10 UTCGHSA enrichment
  10. 2026-09-13 16:46 UTCEPSS rescore
  11. 2026-09-13 12:56 UTCGHSA enrichment
  12. 2026-09-13 08:40 UTCGHSA enrichment
  13. 2026-09-13 04:26 UTCGHSA enrichment
  14. 2026-09-13 00:12 UTCGHSA enrichment
  15. 2026-09-12 18:23 UTCEG score recompute
  16. 2026-09-12 18:23 UTCGHSA enrichment
  17. 2026-09-12 15:00 UTCEPSS rescore
  18. 2026-09-12 13:56 UTCGHSA enrichment
  19. 2026-09-12 09:42 UTCGHSA enrichment
  20. 2026-09-12 05:26 UTCGHSA enrichment
  21. 2026-09-12 01:09 UTCGHSA enrichment
  22. 2026-09-11 20:55 UTCGHSA enrichment
  23. 2026-09-11 16:41 UTCEG score recompute
  24. 2026-09-11 16:41 UTCGHSA enrichment
  25. 2026-09-11 14:52 UTCEPSS rescore
Show 75 more
  1. 2026-09-11 09:36 UTCEPSS rescore
  2. 2026-09-11 07:23 UTCGHSA enrichment
  3. 2026-09-11 03:07 UTCGHSA enrichment
  4. 2026-09-10 20:56 UTCGHSA enrichment
  5. 2026-09-10 15:05 UTCEG score recompute
  6. 2026-09-10 15:05 UTCGHSA enrichment
  7. 2026-09-10 09:34 UTCEPSS rescore
  8. 2026-09-09 08:53 UTCEG score recompute
  9. 2026-09-09 08:53 UTCGHSA enrichment
  10. 2026-09-08 22:00 UTCEPSS rescore
  11. 2026-09-08 01:43 UTCGHSA enrichment
  12. 2026-09-07 21:28 UTCEG score recompute
  13. 2026-09-07 21:28 UTCGHSA enrichment
  14. 2026-09-07 16:01 UTCEPSS rescore
  15. 2026-09-06 16:57 UTCEG score recompute
  16. 2026-09-06 16:57 UTCGHSA enrichment
  17. 2026-09-06 13:47 UTCEPSS rescore
  18. 2026-09-06 12:42 UTCGHSA enrichment
  19. 2026-09-06 08:27 UTCGHSA enrichment
  20. 2026-09-06 03:57 UTCGHSA enrichment
  21. 2026-09-05 23:41 UTCGHSA enrichment
  22. 2026-09-05 19:27 UTCEG score recompute
  23. 2026-09-05 19:27 UTCGHSA enrichment
  24. 2026-09-05 06:57 UTCGHSA enrichment
  25. 2026-09-04 17:12 UTCEG score recompute
  26. 2026-09-04 17:12 UTCGHSA enrichment
  27. 2026-09-04 12:58 UTCEG score recompute
  28. 2026-09-04 12:58 UTCGHSA enrichment
  29. 2026-09-04 05:06 UTCEPSS rescore
  30. 2026-09-02 14:11 UTCEPSS rescore
  31. 2026-09-01 23:20 UTCEG score recompute
  32. 2026-09-01 23:20 UTCGHSA enrichment
  33. 2026-09-01 13:53 UTCEPSS rescore
  34. 2026-09-01 04:39 UTCEPSS rescore
  35. 2026-08-31 07:53 UTCGHSA enrichment
  36. 2026-08-31 03:12 UTCGHSA enrichment
  37. 2026-08-30 22:58 UTCEG score recompute
  38. 2026-08-30 22:58 UTCGHSA enrichment
  39. 2026-08-30 19:17 UTCEPSS rescore
  40. 2026-08-30 18:44 UTCGHSA enrichment
  41. 2026-08-30 14:30 UTCGHSA enrichment
  42. 2026-08-30 10:16 UTCGHSA enrichment
  43. 2026-08-30 04:43 UTCEG score recompute
  44. 2026-08-30 04:43 UTCGHSA enrichment
  45. 2026-08-30 01:22 UTCEPSS rescore
  46. 2026-08-30 00:28 UTCEG score recompute
  47. 2026-08-30 00:28 UTCGHSA enrichment
  48. 2026-08-28 21:41 UTCEPSS rescore
  49. 2026-08-28 01:29 UTCGHSA enrichment
  50. 2026-08-27 21:07 UTCGHSA enrichment
  51. 2026-08-27 14:26 UTCEG score recompute
  52. 2026-08-27 14:26 UTCGHSA enrichment
  53. 2026-08-27 14:25 UTCEPSS rescore
  54. 2026-08-27 10:09 UTCGHSA enrichment
  55. 2026-08-27 04:45 UTCGHSA enrichment
  56. 2026-08-27 00:08 UTCGHSA enrichment
  57. 2026-08-26 19:54 UTCEG score recompute
  58. 2026-08-26 19:54 UTCGHSA enrichment
  59. 2026-08-26 14:46 UTCEPSS rescore
  60. 2026-08-26 12:42 UTCGHSA enrichment
  61. 2026-08-26 08:17 UTCGHSA enrichment
  62. 2026-08-26 04:02 UTCGHSA enrichment
  63. 2026-08-25 23:46 UTCGHSA enrichment
  64. 2026-08-25 19:32 UTCGHSA enrichment
  65. 2026-08-25 15:18 UTCEG score recompute
  66. 2026-08-25 15:18 UTCGHSA enrichment
  67. 2026-08-25 13:48 UTCEPSS rescore
  68. 2026-08-25 11:05 UTCGHSA enrichment
  69. 2026-08-25 06:51 UTCGHSA enrichment
  70. 2026-08-25 02:36 UTCGHSA enrichment
  71. 2026-08-24 22:22 UTCGHSA enrichment
  72. 2026-08-24 18:08 UTCEG score recompute
  73. 2026-08-24 18:08 UTCGHSA enrichment
  74. 2026-08-24 12:10 UTCEG score recompute
  75. 2026-08-24 12:10 UTCGHSA enrichment

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 44.9% 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.

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