Vulnerability-Lookup

GHSA-PG6G-JF8C-49P7

Vulnerability from github – Published: 2026-07-10 15:31 – Updated: 2026-07-10 15:31

Details

Vikunja before 2.2.1 contains an authorization flaw where the LinkSharing.ReadAll endpoint exposes share hashes to users with read access, enabling permission escalation to admin-level shares. The GetTaskAttachment endpoint performs permission checks against user-supplied task IDs but fetches attachments by sequential ID without verifying ownership, allowing attackers to download and delete all file attachments across all projects instance-wide.

Severity

9.8 (Critical)


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

9.3 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-56765"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-10T15:16:43Z",
    "severity": "CRITICAL"
  },
  "details": "Vikunja before 2.2.1 contains an authorization flaw where the LinkSharing.ReadAll endpoint exposes share hashes to users with read access, enabling permission escalation to admin-level shares. The GetTaskAttachment endpoint performs permission checks against user-supplied task IDs but fetches attachments by sequential ID without verifying ownership, allowing attackers to download and delete all file attachments across all projects instance-wide.",
  "id": "GHSA-pg6g-jf8c-49p7",
  "modified": "2026-07-10T15:31:40Z",
  "published": "2026-07-10T15:31:40Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2pv8-4c52-mf8j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56765"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/vikunja-unauthenticated-instance-wide-data-breach-via-link-share-hash-disclosure-chained-with-cross-project-attachment-idor"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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-2026-56765 (GCVE-0-2026-56765)

Vulnerability from cvelistv5 – Published: 2026-07-10 13:57 – Updated: 2026-07-10 17:00

Title

Vikunja - Unauthenticated Instance-Wide Data Breach via Link Share Hash Disclosure Chained with Cross-Project Attachment IDOR

Summary

Severity

9.3 (Critical)


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

9.8 (Critical)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-10 16:40 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-unau…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
Vikunja	Vikunja	Affected: 0 , < 2.2.1 (semver) Unaffected: 2.2.1 (semver) cpe:2.3:a:vikunja:vikunja::::::::

Date Public

2026-03-23 00:00

Credits

offset

Show details on NVD website

JSON

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  "containers": {
    "adp": [
      {
        "metrics": [
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            "other": {
              "content": {
                "id": "CVE-2026-56765",
                "options": [
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                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-10T16:40:04.075201Z",
                "version": "2.0.3"
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        "providerMetadata": {
          "dateUpdated": "2026-07-10T17:00:55.985Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
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            "tags": [
              "exploit"
            ],
            "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-2pv8-4c52-mf8j"
          }
        ],
        "title": "CISA ADP Vulnrichment"
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            "subConfidentialityImpact": "NONE",
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      "references": [
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      ],
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    "dateReserved": "2026-06-22T21:55:17.942Z",
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.