CVE-2024-21643Network attack vector

Server-side request forgery via trusted jku claim

Published Jan 10, 2024 · Updated Jun 10, 2025

SSRF in IdentityModel Extensions for .NET before 6.34.0 and 7.0.0-preview through 7.1.1 allows remote authenticated users to issue HTTP GET requests. SignedHttpRequestValidator trusts the token's jku claim by default and retrieves a proof-of-possession key from the attacker-selected URL without restricting trusted domains. Exploitation requires a service that validates Signed HTTP Requests and a low-privileged remote user able to supply one, causing the service to access remote, internal, or local HTTP resources.

CVSS severity7.1
High
EPSS probability2.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in IdentityModel Extensions for .NET before 6.34.0 and 7.0.0-preview through 7.1.1 allows remote authenticated users to issue HTTP GET requests. SignedHttpRequestValidator trusts the token's jku claim by default and retrieves a proof-of-possession key from the attacker-selected URL without restricting trusted domains. Exploitation requires a service that validates Signed HTTP Requests and a low-privileged remote user able to supply one, causing the service to access remote, internal, or local HTTP resources.

The record

CVE
CVE-2024-21643
Published
Jan 10, 2024
Updated
Jun 10, 2025
Vendor
Microsoft
Product
IdentityModel Extensions for .NET
Classifications
CWE-94, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 10, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 10, 2025Record 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=< 6.34.0
  2. Affected versionversion=>= 7.0.0-preview, < 7.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · IdentityModel Extensions for .NETversion=< 6.34.0; version=>= 7.0.0-preview, < 7.1.2

Published CVSS scores

7.1GitHubCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1190Exploit Public-Facing Application

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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