Vikunja: OIDC email-fallback account linking ignores email_verified, enabling local-account takeover

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.5 · 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 · score source

EPSS

• CVE-2026-62367: 0.09% estimated exploitation activity in the next 30 days; percentile 0.37 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary With the per-provider OIDC emailfallback option enabled, Vikunja links an SSO login to a pre-existing local (username+password) account using only the email claim — no emailverified (or Microsoft xmsedov) check and no password check, on the unauthenticated callback. An attacker who can make the configured issuer emit a token bearing a victim's email logs in as that victim with a full session and no victim interaction (the nOAuth / Grafana CVE-2023-3128 class). The 2.3.0 fix for GHSA-8jvc-mcx6-r4cg added a TOTP gate, not an emailverified gate, so users without TOTP remain exposed. Details References are pkg/modules/auth/openid/openid.go at HEAD. Identity is first resolved on the immutable (issuer, subject) pair (openid.go:428). On a subject miss with emailfallback on, fallbackSearchUsers adds an email-only lookup against local accounts: getUser resolves this via s.Get(), which ANDs non-zero fields - WHERE issuer='local' AND email=?. Local users always have Issuer="local"…

Published by the source

9 Oct 2026, 20:49 UTC

Last modified by the source

19 Oct 2026, 21:31 UTC

Source last checked

26 Oct 2026, 15:32 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-xv7q-fvmc-jx96

2. Revision 3 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6758

4. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-xv7q-fvmc-jx96

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# Patch Next advisory brief: CVE-2026-62367

Advisory: Vikunja: OIDC email-fallback account linking ignores email_verified, enabling local-account takeover
IDs: CVE-2026-62367, GHSA-xv7q-fvmc-jx96
Record: https://patchnext.com/advisories/cve-2026-62367 (revision 4, source checked 26 Oct 2026, 15:32 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: code.vikunja.io/api 2.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go code.vikunja.io/api: affected >= 1.0.0, <= 2.3.0; fixed in 2.4.0

## Suggested inspection (read-only)
- Go code.vikunja.io/api: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on code.vikunja.io/api.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GO-2026-6758 (OSV record GO-2026-6758 lists affected ranges: Go code.vikunja.io/api >=0)
- Verified: https://osv.dev/vulnerability/GHSA-xv7q-fvmc-jx96 (OSV record GHSA-xv7q-fvmc-jx96 lists affected ranges: Go code.vikunja.io/api >=1.0.0 <2.4.0 (fixed))
- Verified: https://github.com/advisories/GHSA-xv7q-fvmc-jx96 (GitHub-reviewed advisory GHSA-xv7q-fvmc-jx96 lists affected ranges: Go code.vikunja.io/api >=1.0.0 <=2.3.0)

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