How severe is CVE-2024-39694?

CVE-2024-39694 has a CVSS score of 4.7/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2024-39694?

CVE-2024-39694 affects the following packages: Duende.IdentityServer (NuGet), Duende.IdentityServer (NuGet), Duende.IdentityServer (NuGet), Duende.IdentityServer (NuGet), Duende.IdentityServer (NuGet), IdentityServer4 (NuGet). Ecosystems affected: NuGet.

How do I fix CVE-2024-39694?

Update Duende.IdentityServer to 7.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-39694 is resolved across your whole dependency graph.

How do I detect CVE-2024-39694 in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Duende.IdentityServer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-39694 if there is no patch (or I can't update yet)?

Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Is CVE-2024-39694 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-39694 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-39694?

CVE-2024-39694 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 45th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-39694?

CVE-2024-39694 is classified as Open Redirect (CWE-601). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-39694 published, and has it been updated?

CVE-2024-39694 was published on July 31, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

.NET

.NET NuGet

Not in CISA KEV

MEDIUM severity

CVE-2024-39694 — Duende.IdentityServer

MEDIUMFix: DuendeSoftware/IdentityServer@269ca21

CVE-2024-39694 is a medium-severity (CVSS 4.7) Open Redirect vulnerability in Duende.IdentityServer. A fix is available for Duende.IdentityServer — see the affected versions and patch details below.

Duende IdentityServer Open Redirect vulnerability

Also known asGHSA-ff4q-64jc-gx98

Published

Jul 31, 2024

Updated

Oct 28, 2026

Affected

6 pkgs

Patched

5 / 6

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-39694.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

6 pkgs affected

.NETDuende.IdentityServer.NETDuende.IdentityServer.NETDuende.IdentityServer.NETDuende.IdentityServer.NETDuende.IdentityServer.NETIdentityServer4

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Impact

It is possible for an attacker to craft malicious Urls that certain functions in IdentityServer will incorrectly treat as local and trusted. If such a Url is returned as a redirect, some browsers will follow it to a third-party, untrusted site.

Note: by itself, this vulnerability does not allow an attacker to obtain user credentials, authorization codes, access tokens, refresh tokens, or identity tokens. An attacker could however exploit this vulnerability as part of a phishing attack designed to steal user credentials.

Affected Methods

In the DefaultIdentityServerInteractionService, the GetAuthorizationContextAsync method may return non-null and the IsValidReturnUrl method may return true for malicious Urls, indicating incorrectly that they can be safely redirected to.

UI code calling these two methods is the most commonly used code path that will expose the vulnerability. The default UI templates rely on this behavior in the Login, Challenge, Consent, and Account Creation pages. Customized user interface code might also rely on this behavior. The following uncommonly used APIs are also vulnerable:
The ServerUrlExtensions.GetIdentityServerRelativeUrl, ReturnUrlParser.ParseAsync and OidcReturnUrlParser.ParseAsync methods may incorrectly return non-null, and the ReturnUrlParser.IsValidReturnUrl and OidcReturnUrlParser.IsValidReturnUrl methods may incorrectly return true for malicious Urls.

Patches

This vulnerability is fixed in the following versions of Duende.IdentityServer:

7.0.6
6.3.10
6.2.5
6.1.8
6.0.5

Duende.IdentityServer 5.1 and earlier and all versions of IdentityServer4 are no longer supported and will not be receiving updates.

Workarounds

If upgrading is not possible, use IUrlHelper.IsLocalUrl from ASP.NET Core 5.0 or later to validate return Urls in user interface code in the IdentityServer host.

Affected Packages

6 total 5 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`Duende.IdentityServer`	≥ 7.0.0-preview.1&&< 7.0.6	7.0.6`dotnet add package Duende.IdentityServer --version 7.0.6`
.NETNuGet	`Duende.IdentityServer`	≥ 6.3.0-preview.1&&< 6.3.10	6.3.10`dotnet add package Duende.IdentityServer --version 6.3.10`
.NETNuGet	`Duende.IdentityServer`	≥ 6.2.0-preview.1&&< 6.2.5	6.2.5`dotnet add package Duende.IdentityServer --version 6.2.5`
.NETNuGet	`Duende.IdentityServer`	≥ 6.1.0-preview.1&&< 6.1.8	6.1.8`dotnet add package Duende.IdentityServer --version 6.1.8`
.NETNuGet	`Duende.IdentityServer`	≥ 6.0.0-preview.1&&< 6.0.5	6.0.5`dotnet add package Duende.IdentityServer --version 6.0.5`
.NETNuGet	`IdentityServer4`	all versions	No fix

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Duende.IdentityServer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Duende.IdentityServer to 7.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-39694 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Frequently Asked Questions

### Impact It is possible for an attacker to craft malicious Urls that certain functions in IdentityServer will incorrectly treat as local and trusted. If such a Url is returned as a redirect, some browsers will follow it to a third-party, untrusted site. _Note: by itself, this vulnerability does **not** allow an attacker to obtain user credentials, authorization codes, access tokens, refresh tokens, or identity tokens. An attacker could however exploit this vulnerability as part of a phishing attack designed to steal user credentials._ ### Affected Methods - In the `DefaultIdentityServerInt