Vulnerability-Lookup

GHSA-9XWC-VWWW-QQMW

Vulnerability from github – Published: 2026-08-19 15:32 – Updated: 2026-08-19 15:32

Details

Vikunja through 2.4.0 contains a principal-type confusion vulnerability where LinkSharing principals with id N are treated as user principals with users.id == N at three permission checks lacking type guards. Attackers with a link-share JWT can remove victims from teams, enumerate and delete victim bot users, or read team rosters by exploiting id collisions in the autoincrement space.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

7.7 (High)


                  
                    CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-76216"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-19T14:17:47Z",
    "severity": "HIGH"
  },
  "details": "Vikunja through 2.4.0 contains a principal-type confusion vulnerability where LinkSharing principals with id N are treated as user principals with users.id == N at three permission checks lacking type guards. Attackers with a link-share JWT can remove victims from teams, enumerate and delete victim bot users, or read team rosters by exploiting id collisions in the autoincrement space.",
  "id": "GHSA-9xwc-vwww-qqmw",
  "modified": "2026-08-19T15:32:33Z",
  "published": "2026-08-19T15:32:33Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-32r8-5843-4qw2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-76216"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/vikunja-through-principal-type-confusion-via-linksharing"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-76216 (GCVE-0-2026-76216)

Vulnerability from cvelistv5 – Published: 2026-08-19 14:02 – Updated: 2026-08-20 16:10

Title

Vikunja through 2.4.0 Principal-Type Confusion via LinkSharing

Summary

Severity

7.7 (High)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 16:10 UTC

CWE

CWE-639 - Authorization Bypass Through User-Controlled Key

Assigner

VulnCheck mitre root

References

2 references

URL	Tags
https://github.com/go-vikunja/vikunja/security/ad…	vendor-advisory
https://www.vulncheck.com/advisories/vikunja-thro…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
go-vikunja	vikunja	Affected: 0 , ≤ 2.4.0 (semver) cpe:2.3:a:vikunja:vikunja::::::::

Date Public

2026-08-04 00:00

Credits

manus-use

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JSON

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        "metrics": [
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                "id": "CVE-2026-76216",
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                  },
                  {
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                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-20T16:10:21.585796Z",
                "version": "2.0.3"
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-9XWC-VWWW-QQMW

CVE-2026-76216 (GCVE-0-2026-76216)

Tags

Sightings

Nomenclature