Vikunja before 2.6.0 Denial of Service via Avatar Upload

{
  "id": "127f92ff1ff911939901cf252af01ae578c2797e9554c16213f616bad0682c8a",
  "url": "https://osv.dev/vulnerability/CVE-2026-91971",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Vikunja before 2.6.0 Denial of Service via Avatar Upload",
    "summary": "Vikunja before 2.6.0 fails to apply pixel decode limits to avatar and project-background upload endpoints, allowing authenticated users to upload crafted images that decode to excessive pixel counts. Attackers can upload small images with extreme aspect ratios that consume significant CPU and memory during processing, causing denial of service through repeated or concurrent uploads.",
    "evidence": "osv:CVE-2026-91971",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-91971",
      "aliases": [
        "CVE-2026-91971",
        "GHSA-4vh2-39rq-rq8j",
        "GO-2026-6717"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/go-vikunja/vikunja",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "a4218eeb8fb3ada95e14a2331731524c9120d5bd"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.6.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.6.0"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.5.0",
            "v2.4.0",
            "v2.3.0",
            "v2.2.2",
            "v2.2.1",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0",
            "v1.1.0",
            "v1.0.0",
            "v1.0.0-rc4",
            "v1.0.0-rc3",
            "v1.0.0-rc2",
            "v1.0.0-rc1",
            "v1.0.0-rc0",
            "v0.24.1",
            "v0.23.0",
            "v0.22.1",
            "v0.22.0",
            "v0.21.0",
            "v0.20.4",
            "v0.20.3",
            "v0.20.1",
            "v0.20.0",
            "v0.19.2",
            "v0.19.1",
            "v0.19.0",
            "v0.18.1",
            "v0.18.0",
            "v0.17.0",
            "v0.16.0",
            "v0.15.0",
            "v0.14.0",
            "v0.13",
            "v0.12",
            "v0.11",
            "v0.10",
            "v0.9",
            "v0.8",
            "v0.7",
            "v0.6",
            "v0.5",
            "v0.4",
            "v0.3",
            "v0.2",
            "v0.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-91971.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.287689921Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91971.json",
        "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-4vh2-39rq-rq8j",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-91971",
        "https://www.vulncheck.com/advisories/vikunja-before-2.6.0-denial-of-service-via-avatar-upload"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-400"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91971.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-91971",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496265,
  "published_at": "2026-09-15T15:18:22.129+00:00"
}