Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Vikunja versions from 1.0.0 before 2.4.0 are affected when the per-provider OIDC emailfallback option is enabled. An unauthenticated attacker who can get the configured identity provider to issue a token with a victim's email address can log in as a local account holder without the password and gain a full session, though TOTP-enabled users are protected. Upgrade to Vikunja 2.4.0 or later. The source gives no workaround besides disabling emailfallback, which is the default.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 4.0 | 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 | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0009, the 1st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:11 UTC First seen by agentprime
- 31 Oct 2026, 14:11 UTC Confirmed by OSV