How severe is CVE-2024-21643?

CVE-2024-21643 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2024-21643 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-21643?

CVE-2024-21643 affects Microsoft Identitymodel Extensions. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2024-21643?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2024-21643 have an EU (EUVD) identifier?

Yes. CVE-2024-21643 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-0423.

When was CVE-2024-21643 published?

CVE-2024-21643 was published on 2024-01-10 and last updated on 2026-06-17.

CVE-2024-21643

CVE-2024-21643 is a high-severity vulnerability in Microsoft Identitymodel Extensions with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-0423
Weakness: CWE-94
Affected product: Microsoft Identitymodel Extensions
Published: 2024-01-10
Last modified: 2026-06-17

Description

IdentityModel Extensions for .NET provide assemblies for web developers that wish to use federated identity providers for establishing the caller's identity. Anyone leveraging the `SignedHttpRequest`protocol or the `SignedHttpRequestValidator`is vulnerable. Microsoft.IdentityModel trusts the `jku`claim by default for the `SignedHttpRequest`protocol. This raises the possibility to make any remote or local `HTTP GET` request. The vulnerability has been fixed in Microsoft.IdentityModel.Protocols.SignedHttpRequest. Users should update all their Microsoft.IdentityModel versions to 7.1.2 (for 7x) or higher, 6.34.0 (for 6x) or higher.

Frequently asked questions

What is CVE-2024-21643?: IdentityModel Extensions for .NET provide assemblies for web developers that wish to use federated identity providers for establishing the caller's identity. Anyone leveraging the `SignedHttpRequest`protocol or the `SignedHttpRequestValidator`is vulnerable. Microsoft.IdentityModel trusts the `jku`claim by default for the `SignedHttpRequest`protocol. This raises the possibility to make any remote or local `HTTP GET` request. The vulnerability has been fixed in Microsoft.IdentityModel.Protocols.SignedHttpRequest. Users should update all their Microsoft.IdentityModel versions to 7.1.2 (for 7x) or higher, 6.34.0 (for 6x) or higher.
How severe is CVE-2024-21643?: CVE-2024-21643 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2024-21643 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-21643?: CVE-2024-21643 affects Microsoft Identitymodel Extensions. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-21643?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2024-21643 have an EU (EUVD) identifier?: Yes. CVE-2024-21643 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-0423.
When was CVE-2024-21643 published?: CVE-2024-21643 was published on 2024-01-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:microsoft:identitymodel_extensions:*:*:*:*:*:.net:*:*

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