Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
GHSA-9rg3-v78m-26q8: Vikunja (Go module code.vikunja.io/api) versions from 1.0.0 before 2.6.0 let an API token that only has task read permissions see comments, reactions, and time entry counts on tasks through the expand query parameter, which bypasses the token's scopes for those data groups. An attacker needs a token with only task read access, and can read comment bodies and reactions on tasks the token owner can already access. Upgrade to version 2.6.0 or later.
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 |
|---|---|---|---|---|
| 5.3 | Medium | 4.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N | CNA (VulnCheck) |
- CISA KEV Not listed.
- EPSS 0.0031, the 23rd percentile, on 7 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
Sources
- GitHub Advisory Database: GHSA-9rg3-v78m-26q8
- OSV: GHSA-9rg3-v78m-26q8
- github.com/go-vikunja/vikunja/security/advisories/GHSA-9rg3-v78m-26q8
- nvd.nist.gov/vuln/detail/CVE-2026-91983
- github.com/go-vikunja/vikunja/pull/3688
- github.com/go-vikunja/vikunja/commit/077dc4de79ce6f1ab59215a2c7bf9b30423685f2
- github.com/go-vikunja/vikunja
- github.com/go-vikunja/vikunja/releases/tag/v2.6.0
- www.vulncheck.com/advisories/vikunja-before-2.6.0-api-token-scope-bypass-via-expand-parameter