CVE-2026-89209

waiting for further signalsZero needs more public information before it can validate it.

GHSA-c6gm-hvjc-mr8p ↗EUVD-2026-109739 ↗

no check availablenot proven exploitable
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.
Siemens Mendix SAML (Mendix 10 compatible) < V4.2.4; < V3.6.29
fixed in V4.2.4, V3.6.29
CWE-294 Authentication Bypass by Capture-replay
ETK-2026-2643Zero's internal tracking ID, independent of the CVE number., permanent identifier
4h 05msince last run
22mAI analysisAnalysis: how long the AI spent reversing this signal.
timeline
0 = cve.org publication
trigger signal (cve.org) +0hwaiting for further signals+27h17m
0
+2h
+4h
+6h
+8h
+10h

description

Mendix SAML modules used with Mendix 9, 10, or 11 may accept a previously valid SAML authentication response again during IdP-initiated sign-in. An unauthenticated remote party who has obtained such a valid response may be able to access the protected application as its associated user.

mitigation

Upgrade Mendix SAML for Mendix 10 and 11 to V4.2.4 or later, and upgrade the Mendix 9-compatible module to V3.6.29 or later. Prioritize systems that permit IdP-initiated authentication.

fixed in V4.2.4, V3.6.29

check
no
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.
–
agent run time
22m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
2026-10-26 10:41Z
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, not validated: no deterministic check could cover this one, and no technique passed our review.

source signals

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

  1. 2026-10-26 10:41Z
    cve_org: trigger signal, started the run

this entry in the feed

GET /api/v1/feed/CVE-2026-89209

{
  "etk_id": "ETK-2026-2643",
  "cve_id": "CVE-2026-89209",
  "display_id": "CVE-2026-89209",
  "ghsa_id": "GHSA-c6gm-hvjc-mr8p",
  "euvd_id": "EUVD-2026-109739",
  "status": "published",
  "anchor_state": "anchored",
  "title": "SAML assertion replay in Mendix SAML",
  "summary": "Mendix SAML modules used with Mendix 9, 10, or 11 may accept a previously valid SAML authentication response again during IdP-initiated sign-in. An unauthenticated remote party who has obtained such a valid response may be able to access the protected application as its associated user.",
  "mitigation": "Upgrade Mendix SAML for Mendix 10 and 11 to V4.2.4 or later, and upgrade the Mendix 9-compatible module to V3.6.29 or later. Prioritize systems that permit IdP-initiated authentication.",
  "vendor": "Siemens",
  "product": "Mendix SAML (Mendix 10 compatible)",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 0, < V4.2.4"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "V4.2.4"
      ],
      "package_name": "Mendix SAML (Mendix 10 compatible)",
      "purl": null
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 0, < V4.2.4"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "V4.2.4"
      ],
      "package_name": "Mendix SAML (Mendix 11 compatible)",
      "purl": null
    },
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 0, < V3.6.29"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "V3.6.29"
      ],
      "package_name": "Mendix SAML (Mendix 9 compatible)",
      "purl": null
    }
  ],
  "cwes": [
    294
  ],
  "cvss_score": 7.6,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "contextual",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 22.145054033333334,
  "t0_at": "2026-10-26T10:41:01.088000+00:00",
  "signals": {
    "trigger_signal": {
      "at": "2026-10-26T10:41:01.088000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-26T10:41:01.088000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-89209"
    }
  }
}

published 2026-10-26 11:12Z
last change 2026-10-27 16:29Z

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