Auth bypass in Maybe-Finance Maybe
CVE-2026-63100
Maybe through 0.6.0 contains a missing authorization vulnerability that allows authenticated low-privilege member-role users to access and modify global hosting settings by exploiting unprotected show and update actions in the Settings::HostingsController, where the before_action ensure_admin filter is applied only to the clear_cache action. Attackers can read the operator's Synth API key rendered in plaintext via a form field value attribute, overwrite it with an attacker-controlled value, toggle public registration settings, and disable email confirmation requirements to disrupt the entire instance.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (27.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Maybe-Finance Maybe — versions 0
Weakness classification (CWE)
References
- github.com/geo-chen/oss/blob/main/maybe.md (technical-description, exploit)
- www.vulncheck.com/advisories/maybe-missing-authorization-via-hostingscontroller… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-63100?
- CVE-2026-63100 is a medium-severity vulnerability in Maybe-Finance Maybe, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-07-17.
- How severe is CVE-2026-63100?
- Medium severity. CVSS v3 base score is 6.5 out of 10.