CVE-2026-108718: Auth Bypass (CVSS 8.1)

Description

Rill 0.77.0 through 0.90.5 contains a missing authorization vulnerability in the admin OAuth server that issues authorization codes to dynamically registered clients without user consent. Attackers can register a client with the long_lived_access_token scope and lure a user to an authorization link, obtaining a non-expiring API token with the user's full permissions.

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CVSS v3.1 Score

8.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0027

Probability of exploitation

0.18%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://github.com/rilldata/rill https://github.com/rilldata/rill/blob/b9ea8c6f215e56c4c0848771e70b3ec38346eacc/admin/server/auth/handlers.go#L650-L697 https://github.com/rilldata/rill/blob/b9ea8c6f215e56c4c0848771e70b3ec38346eacc/admin/server/auth/mcp_oauth.go#L77-L153 https://github.com/rilldata/rill/blob/b9ea8c6f215e56c4c0848771e70b3ec38346eacc/admin/server/auth/pkce.go#L173-L214 https://hackmd.io/@haind03/rill-oauth-open-registration-long-lived-token https://www.vulncheck.com/advisories/rill-0.77.0-through-0.90.5-oauth-missing-authorization-via-dynamic-client-registration

Frequently Asked Questions

What is CVE-2026-108718? +

Rill 0.77.0 through 0.90.5 contains a missing authorization vulnerability in the admin OAuth server that issues authorization codes to dynamically registered clients without user consent. Attackers can register a client with the long_lived_access_token scope and lure a user to an authorization link, obtaining a non-expiring API token with the user's full permissions. It has a CVSS v3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-108718? +

CVE-2026-108718 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0027, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-108718? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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