CVE-2026-91983 json
Vikunja before 2.6.0 API Token Scope Bypass via expand Parameter
published 2026-09-15 54 d ago modified 2026-10-19 20 d ago also GHSA-9rg3-v78m-26q8 , GO-2026-6726 , EUVD-2026-78654
- cvss
- 4.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 23%
- public exploits
- 0
- none known
Summary
Vikunja before 2.6.0 contains an API token scope bypass vulnerability in task read endpoints where authorization fails to inspect query string parameters. Attackers with limited token scopes can use the expand parameter to access restricted data like comments, reactions, and time entries without proper permission verification.
Patch / fix
- go code.vikunja.io/api 2.6.0
- go-vikunja vikunja 2.6.0
- github.com/go-vikunja/vikunja@077dc4d commit
- github.com/go-vikunja/vikunja#3688 pull request
- github.com/go-vikunja/vikunja/releases/tag/v2.6.0 release
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 54 d ago
Exploit prediction
0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/go-vikunja/vikunja/security/advisories/GHSA-9rg3-v78m-26q8 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 5.3 | 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 | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
| CNA | 4.0 | 5.3 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | code.vikunja.io/api | >=1.0.0, <2.6.0 all versions |
2.6.0 |
Affected products
- go-vikunja vikunja
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
-
github.com
/go-vikunja/vikunja/pull/3688
web
-
github.com
/go-vikunja/vikunja/commit/077dc4de79ce6f1ab59215a2c7bf9b30423685f2
web
-
github.com
/go-vikunja/vikunja/security/advisories/GHSA-9rg3-v78m-26q8
vendor-advisory, exploit, web, advisory
-
vulncheck.com
/advisories/vikunja-before-2.6.0-api-token-scope-bypass-via-expand-parameter
third-party-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-91983
advisory
-
github.com
/go-vikunja/vikunja
package
-
github.com
/go-vikunja/vikunja/releases/tag/v2.6.0
web
Sources
- CVE List CVE-2026-91983
- GitHub Advisory GHSA-9rg3-v78m-26q8
- NVD CVE-2026-91983
- OSV GO-2026-6726
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.