CVE-2026-41164 nuts-node: JWT type confusion in v1 access token introspection allows VP replay as access token
Attackers can replay Verifiable Presentation JWTs as valid access tokens due to missing type validation, bypassing authentication controls.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-41164?
CVE-2026-41164 is a medium-severity authentication bypass vulnerability in nuts-foundation nuts-node, published on 26 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
nuts-node is the reference implementation of the Nuts specification. Prior to 6.2.3 and 5.4.31, the v1 access token introspection endpoint (/auth/v1/introspect_access_token) accepts any JWT signed by a key present on the node, without validating the JWT type, issuer-to-key binding, or required claims. This allows a Verifiable Presentation (VP) JWT to be replayed as an access token and receive an active: true introspection response. This vulnerability is fixed in 6.2.3 and 5.4.31.
Weakness: CWE-345
Which versions are affected by CVE-2026-41164?
3 open source packages ship an affected version, including github.com/nuts-foundation/nuts-node.
| Package | Affected | Fixed in |
|---|---|---|
github.com/nuts-foundation/nuts-node Go | All versions | None |
github.com/nuts-foundation/nuts-node Go | All versions to 1.1.0 | None |
github.com/nuts-foundation/nuts-node Go | All versions to 1.1.0 | None |
How do I fix CVE-2026-41164?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-41164 being exploited?
There is no known exploitation of CVE-2026-41164 in the wild and no public exploit code.
Sources
Also known as GHSA-9hmg-827w-9rhj, GO-2026-5291.