CVE-2026-28787

CRITICALNVD 9.09.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.0 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
9.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.0Exploit: None knownExposed: 0

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

OneUptime is a solution for monitoring and managing online services. In version 10.0.11 and prior, the WebAuthn authentication implementation does not store the challenge on the server side. Instead, the challenge is returned to the client and accepted back from the client request body during verification. This violates the WebAuthn specification (W3C Web Authentication Level 2, §13.4.3) and allows an attacker who has obtained a valid WebAuthn assertion (e.g., via XSS, MitM, or log exposure) to replay it indefinitely, completely bypassing the second-factor authentication. No known patches are available.

CVSS v3
9.0
EG Score
9.0(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity90% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

March 6, 2026

Last Modified

June 17, 2026

Advisory Details (1)

Auto-updated Jul 28, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

WebAuthn 2FA bypass: server accepts client-supplied challenge instead of server-stored value, allowing credential replay · Advisory · OneUptime/oneuptime · GitHub

https://github.com/OneUptime/oneuptime/security/advisories/GHSA-gjjc-pcwp-c74m

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
npm@oneuptime/common—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@oneuptime/common———

Weakness Classification(2)

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

Data Freshness Timeline

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

Frequently asked(5)

What is CVE-2026-28787?
CVE-2026-28787 is a critical vulnerability published on March 6, 2026. OneUptime is a solution for monitoring and managing online services. In version 10.0.11 and prior, the WebAuthn authentication implementation does not store the challenge on the server side. Instead, the challenge is returned to the client and accepted back from the client request body during…
When was CVE-2026-28787 disclosed?
CVE-2026-28787 was first published in the National Vulnerability Database on March 6, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-28787 actively exploited?
CVE-2026-28787 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.7% of all scored CVEs.
What is the CVSS score of CVE-2026-28787?
CVE-2026-28787 has a CVSS v3 base score of 9.0 (NVD).
How do I remediate CVE-2026-28787?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-28787, 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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