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Fencer Vulns
medium 6.8

CVE-2026-89209 json

A vulnerability has been identified in Mendix SAML (Mendix 10 compatible) (All versions < V4.2.4), Mendix SAML (Mendix 11 compatible) (All…

published 2026-10-26 13 d ago modified 2026-10-31 9 d ago also EUVD-2026-109739

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

A vulnerability has been identified in Mendix SAML (Mendix 10 compatible) (All versions < V4.2.4), Mendix SAML (Mendix 11 compatible) (All versions < V4.2.4), Mendix SAML (Mendix 9 compatible) (All versions < V3.6.29). Affected versions of the module do not properly protect against SAML assertion replay in IdP-initiated authentication flows. This could allow unauthenticated remote attackers to gain unauthorized access to the application by replaying a valid SAML response.

Patch / fix

  • Siemens Mendix SAML (Mendix 10 compatible) V4.2.4
  • Siemens Mendix SAML (Mendix 11 compatible) V4.2.4
  • Siemens Mendix SAML (Mendix 9 compatible) V3.6.29

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-26-302-01 updated cvss 6.8

Siemens Mendix SAML Module

  • Siemens Mendix SAML (Mendix 9 compatible) < 3.6.29
    affected: fixed in V3.6.29, mitigation marketplace.mendix.com
  • Siemens Mendix SAML (Mendix 10 compatible) < 4.2.4 Siemens Mendix SAML (Mendix 11 compatible) < 4.2.4
    affected: fixed in V4.2.4, mitigation marketplace.mendix.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
9 d ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
CNA 4.0 7.6 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
CNA 4.0 7.6 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • Siemens Mendix SAML (Mendix 10 compatible)
  • Siemens Mendix SAML (Mendix 11 compatible)
  • Siemens Mendix SAML (Mendix 9 compatible)

Classification

Weakness
  • CWE-294 Authentication Bypass by Capture-replay

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.