Duende.AccessTokenManagement race condition when concurrently retrieving customized Client Credentials Access Tokens

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N · score source

EPSS

• CVE-2025-26620: 0.39% estimated exploitation activity in the next 30 days; percentile 33.37 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Duende.AccessTokenManagement contains a race condition when requesting access tokens using the client credentials flow. Concurrent requests to obtain an access token using differing protocol parameters can return access tokens obtained with the wrong scope, resource indicator, or other protocol parameters. Such usage is somewhat atypical, and only a small percentage of users are likely to be affected. Details Duende.AccessTokenManagement can request access tokens using the client credentials flow in several ways. In basic usage, the client credentials flow is configured once and the parameters do not vary. In more advanced situations, requests with varying protocol parameters may be made by calling specific overloads of these methods: - HttpContext.GetClientAccessTokenAsync() - IClientCredentialsTokenManagementService.GetAccessTokenAsync() There are overloads of both of these methods that accept a TokenRequestParameters object that customizes token request parameters.…

Published by the source

19 Feb 2025, 17:47 UTC

Last modified by the source

19 Feb 2025, 17:47 UTC

Source last checked

26 Oct 2026, 17:03 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qxj7-2x7w-3mpp

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# Patch Next advisory brief: CVE-2025-26620

Advisory: Duende.AccessTokenManagement race condition when concurrently retrieving customized Client Credentials Access Tokens
IDs: CVE-2025-26620, GHSA-qxj7-2x7w-3mpp
Record: https://patchnext.com/advisories/cve-2025-26620 (revision 1, source checked 26 Oct 2026, 17:03 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: duende.accesstokenmanagement 3.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet duende.accesstokenmanagement: affected < 3.2.0; fixed in 3.2.0

## Suggested inspection (read-only)
- NuGet duende.accesstokenmanagement: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on duende.accesstokenmanagement.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-qxj7-2x7w-3mpp (GitHub-reviewed advisory GHSA-qxj7-2x7w-3mpp lists affected ranges: NuGet duende.accesstokenmanagement >=0 <3.2.0)

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