CVE-2023-41890Network attack vector

Authentication bypass via mismatched SAML issuers

Published Sep 19, 2023 · Updated Oct 15, 2024

Authentication bypass in Sustainsys.Saml2 before 1.0.3 and 2.0.0 through 2.9.1 allows remote attackers to forge identity claims. Response processing validates the response issuer through signing keys but fails to verify that the assertion issuer matches it or the issuer bound to stored request state. Exploitation requires an application to trust the generated issuer or AuthenticationProperties, enabling substitution of another provider's identity or state.

CVSS severity7.5
High
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Sustainsys.Saml2 before 1.0.3 and 2.0.0 through 2.9.1 allows remote attackers to forge identity claims. Response processing validates the response issuer through signing keys but fails to verify that the assertion issuer matches it or the issuer bound to stored request state. Exploitation requires an application to trust the generated issuer or AuthenticationProperties, enabling substitution of another provider's identity or state.

The record

CVE
CVE-2023-41890
Published
Sep 19, 2023
Updated
Oct 15, 2024
Vendor
Sustainsys
Product
Sustainsys.Saml2
Classifications
CWE-294, CWE-289, T1606.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.0.3
  2. Affected versionversion=>= 2.0.0, < 2.9.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sustainsys · Sustainsys.Saml2version=< 1.0.3; version=>= 2.0.0, < 2.9.2

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
CWE-289Authentication Bypass by Alternate Name
T1606.002SAML Tokens

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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