CVE-2026-105863

validatedZero produced an exploit or a check.

GHSA-66wr-7vmr-p5jq ↗EUVD-2026-93509 ↗

check availableZero validated a working check for it.not proven exploitableZero has a detection check, but hasn't produced a full working exploit yet.
cve.orgpublic pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).kevAttacks confirmed in the real world.
payloadcms payload >= 3.0.0, < 3.90.0; >= 4.0.0-canary.0, < 4.0.0-canary.34
fixed in 3.90.0, 4.0.0-canary.34
CWE-290 Authentication Bypass by Spoofing
ETK-2026-827, permanent identifier
pkg:npm/payload
+8h27mTTV
21mAI analysisAnalysis: how long the AI spent reversing this signal.
Check if you are vulnerable
timeline
0 = trigger signal
trigger signal (cve.org) +0hcheck available+8h27magent stopped
0
+2h
+4h
+6h
+8h

description

Affected Payload deployments can include unintended custom-field values in authentication tokens issued during login. An attacker may obtain a token with improperly populated claims when the deployment maps a custom field to a reserved authentication claim name; this requires both that configuration and an affected release.

mitigation

Upgrade the npm payload package to 3.90.0 or later, or to 4.0.0-canary.34 or later on the canary line. Review custom field mappings and remove mappings to reserved authentication claim names.

fixed in 3.90.0, 4.0.0-canary.34

check
available
exploit
no
automationDeterministic: a check that runs on its own, the same request on every target. Contextual: an agentic technique that needs to be applied per target, for bugs that depend on contextual flows.
contextual
auth requiredWhether an attacker needs an account first, based on the CVSS vector's Privileges Required.
no
EPSSEstimate of the chance this CVE is exploited in the next 30 days. Refreshed daily.
0.38%30th percentile
agent run time
21m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
2026-10-06 16:39Z
Δ to public pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).
–
Δ to kevAttacks confirmed in the real world.
–

outcome

Contextual check: a technique exists and was validated, but no deterministic check could cover this one.

source signals

Public signals that triggered or updated the pipeline. These are inputs for the deltas above.

  1. 2026-10-06 16:39Z
    cve_org: trigger signal, started the run

this entry in the feed

GET /api/v1/feed/CVE-2026-105863

{
  "etk_id": "ETK-2026-827",
  "cve_id": "CVE-2026-105863",
  "display_id": "CVE-2026-105863",
  "ghsa_id": "GHSA-66wr-7vmr-p5jq",
  "euvd_id": "EUVD-2026-93509",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Authentication token claim injection in Payload",
  "summary": "Affected Payload deployments can include unintended custom-field values in authentication tokens issued during login. An attacker may obtain a token with improperly populated claims when the deployment maps a custom field to a reserved authentication claim name; this requires both that configuration and an affected release.",
  "mitigation": "Upgrade the npm payload package to 3.90.0 or later, or to 4.0.0-canary.34 or later on the canary line. Review custom field mappings and remove mappings to reserved authentication claim names.",
  "vendor": "payloadcms",
  "product": "payload",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 3.0.0, < 3.90.0"
      ],
      "ecosystem": "npm",
      "fixed_versions": [
        "3.90.0"
      ],
      "package_name": "payload",
      "purl": "pkg:npm/payload"
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 4.0.0-canary.0, < 4.0.0-canary.34"
      ],
      "ecosystem": "npm",
      "fixed_versions": [
        "4.0.0-canary.34"
      ],
      "package_name": "payload",
      "purl": "pkg:npm/payload"
    }
  ],
  "cwes": [
    290
  ],
  "cvss_score": 9.2,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
  "epss_score": 0.0038,
  "epss_percentile": 0.3014,
  "epss_asof": "2026-10-20",
  "automation": "contextual",
  "check": true,
  "check_confidence_basis": "assessed",
  "exploit": false,
  "pipeline_minutes": 20.85219455,
  "t0_at": "2026-10-06T16:39:44.912000+00:00",
  "signals": {
    "check": {
      "at": "2026-10-07T01:06:19.528558+00:00",
      "days": 0.3517895434953704,
      "is_lower_bound": false,
      "measured_at": "2026-10-06T16:39:44.912000+00:00",
      "url": null
    },
    "trigger_signal": {
      "at": "2026-10-06T16:39:44.912000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-06T16:39:44.912000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-105863"
    }
  }
}

published 2026-10-07 00:56Z
last change 2026-10-21 16:09Z

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