How severe is GHSA-v9xq-2mvm-x8xc?

GHSA-v9xq-2mvm-x8xc has a CVSS score of 3.1/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-v9xq-2mvm-x8xc?

GHSA-v9xq-2mvm-x8xc affects the following packages: Duende.IdentityServer (NuGet). Ecosystems affected: NuGet.

How do I fix GHSA-v9xq-2mvm-x8xc?

Update Duende.IdentityServer to 7.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v9xq-2mvm-x8xc is resolved across your whole dependency graph.

How do I detect GHSA-v9xq-2mvm-x8xc in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Duende.IdentityServer. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-v9xq-2mvm-x8xc if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-v9xq-2mvm-x8xc?

O3 pinpoints whether GHSA-v9xq-2mvm-x8xc is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-v9xq-2mvm-x8xc actively exploited in the wild?

No public exploit code has been indexed for GHSA-v9xq-2mvm-x8xc 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 GHSA-v9xq-2mvm-x8xc?

GHSA-v9xq-2mvm-x8xc has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th 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 GHSA-v9xq-2mvm-x8xc?

GHSA-v9xq-2mvm-x8xc is classified as Improper Authentication (CWE-287). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-v9xq-2mvm-x8xc published, and has it been updated?

GHSA-v9xq-2mvm-x8xc was published on October 28, 2024 and was last updated on October 28, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

.NET NuGet

GHSA-v9xq-2mvm-x8xc

LOW

Duende IdentityServer has insufficient validation of DPoP cnf claim in Local APIs

Also known asCVE-2024-49755

Published

Oct 28, 2024

Updated

Oct 28, 2024

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk23th percentile+0.18%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

.NETDuende.IdentityServer

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

IdentityServer's local API authentication handler performs insufficient validation of the cnf claim in DPoP access tokens. This allows an attacker to use leaked DPoP access tokens at local api endpoints even without possessing the private key for signing proof tokens.

Note that this only impacts custom endpoints within an IdentityServer implementation that have explicitly used the LocalApiAuthenticationHandler for authentication. It does not impact:

OAuth or OIDC protocol endpoints defined by IdentityServer, such as the authorize and token endpoints.
Typical UI pages within an IdentityServer implementation, which are not normally authorized with the local API authentication handler.
The use of DPoP to create sender-constrained tokens in IdentityServer that are consumed by external API resources.
The use of DPoP to sender-constrain refresh tokens issued to public clients.

Are you affected?

This vulnerability only affects IdentityServer implementations that are using the local APIs feature of IdentityServer and have explicitly enabled DPoP for local APIs. The local api authentication handler is configured with a call to either AddLocalApi or AddLocalApiAuthentication, and the opt-in to DPoP for local APIs is enabled via the TokenMode option.

Vulnerable implementations of IdentityServer would have configuration code similar to the following:

services.AddAuthentication()
    .AddLocalApi("local", options => 
    {
        options.TokenMode = LocalApiTokenMode.DPoPAndBearer; // or LocalApiTokenMode.DPoPOnly
    });

Patches

This vulnerability is patched in IdentityServer 7.0.8. Version 6.3 and below are unaffected, as they do not support DPoP in Local APIs.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`Duende.IdentityServer`	≥ 7.0.0&&< 7.0.8	7.0.8

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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Duende.IdentityServer to 7.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v9xq-2mvm-x8xc is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-v9xq-2mvm-x8xc is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-v9xq-2mvm-x8xc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact IdentityServer's local API authentication handler performs insufficient validation of the `cnf` claim in DPoP access tokens. This allows an attacker to use leaked DPoP access tokens at local api endpoints even without possessing the private key for signing proof tokens. Note that this only impacts custom endpoints within an IdentityServer implementation that have explicitly used the `LocalApiAuthenticationHandler` for authentication. It does not impact: - OAuth or OIDC protocol endpoints defined by IdentityServer, such as the authorize and token endpoints. - Typical UI pages within

O3 Security · Impact-Aware SCA

Is GHSA-v9xq-2mvm-x8xc in your dependencies?

O3 detects GHSA-v9xq-2mvm-x8xc across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works