Dashbit nimble_zta up to 0.1.2 cloudflare.ex verify_token signature verification

Summaryinfo

A vulnerability, which was classified as critical, has been found in Dashbit nimble_zta up to 0.1.2. This issue affects the function verify_token of the file lib/nimble_zta/cloudflare.ex. Performing a manipulation results in signature verification. This vulnerability is reported as CVE-2026-91187. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Dashbit nimble_zta up to 0.1.2. This affects the function verify_token of the file lib/nimble_zta/cloudflare.ex. The manipulation with an unknown input leads to a signature verification vulnerability. CWE is classifying the issue as CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Improper Verification of Cryptographic Signature vulnerability in dashbit nimble_zta allows an unauthenticated remote attacker to authenticate as an arbitrary Cloudflare service token. Applications using the Cloudflare Zero Trust authentication strategy are affected. verify_token/2 in lib/nimble_zta/cloudflare.ex matches the result of JOSE.JWT.verify/2 against {_, token, _s}, which discards the boolean verification result and returns the decoded token after a failed signature check. The attacker sends a forged JWT in the cf-access-jwt-assertion header, carrying the expected iss claim and the seven service token claims. verify_iss/2 reads the iss claim from the forged token, so it rejects nothing, and the service token path then returns those claims as the authenticated identity. This issue affects nimble_zta: from 0.1.2 before 0.1.3.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-91187 since 09/15/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 0.1.3 eliminates this vulnerability.

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Productinfo

Vendor

• Dashbit

Name

• nimble_zta

Version

• 0.1.0
• 0.1.1
• 0.1.2

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CPE 2.2info

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