Vulnerability · Published Oct 9, 2026 · Assigned by GitHub_M
CVE-2026-62367Vikunja: OIDC email-fallback account linking ignores email_verified, enabling local-account takeover
High 7.5
In plain English
A high-severity improper authentication in vikunja from go-vikunja. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 0% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Vikunja is an open-source self-hosted task management platform. In versions 1.0.0 through 2.3.0, when an administrator enables the per-provider `emailfallback` option on an OpenID Connect provider, Vikunja links an SSO login to a pre-existing local (username+password) account using only the `email` claim from the IdP. The fallback never checks an `email_verified` (or Microsoft `xms_edov`) signal and never requires the matched account's password. An attacker who can obtain a token from the configured issuer carrying a victim's email logs in as that victim with a full session, with no consent or interaction from the victim. Version 2.4.0 fixes the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | code.vikunja.io/api | 2.4.0 | GHSA-xv7q-fvmc-jx96 |
| Go | code.vikunja.io/api | no fix listed | GO-2026-6758 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| go-vikunja | vikunja | >= 1.0.0, < 2.4.0 |
Weakness: CWE-287, CWE-290, CWE-345 · Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N