Gogs: UploadRepoFiles writes outside repo working tree via committed parent sym

{
  "id": "b9724dc86a4a88900816c5eaa723048d38cecb21a50cd806844ce72a64dc59eb",
  "url": "https://osv.dev/vulnerability/CVE-2026-52811",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Gogs: UploadRepoFiles writes outside repo working tree via committed parent sym",
    "summary": "Gogs is an open source self-hosted Git service. Prior to 0.14.3, (*Repository).UploadRepoFiles checks for symlinks only on the leaf of the upload target (osx.IsSymlink(targetPath)). The siblings UpdateRepoFile, DeleteRepoFile, and GetDiffPreview use hasSymlinkInPath, which lstats every component — UploadRepoFiles is the lone outlier. An attacker with repo-write access plus a multipart upload whose filename contains a literal backslash (preserved by filepath.Base on Linux, then converted to / by pathx.Clean) redirects the write through a previously-committed directory symlink. iox.CopyFile opens the destination with os.Create (no O_NOFOLLOW), so the kernel follows the parent symlink and writes attacker bytes anywhere the gogs UID can write — ~git/.ssh/authorized_keys → SSH foothold, or .git/hooks/post-receive → next-push RCE. This vulnerability is fixed in 0.14.3.",
    "evidence": "osv:CVE-2026-52811",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-52811",
      "aliases": [
        "CVE-2026-52811",
        "GHSA-89mr-xqfv-758m",
        "GO-2026-5249"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/gogs/gogs",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "3ba8aca90e17e5410b7e8b227c9f29256ac3e875"
                },
                {
                  "fixed": "04cb8afbb01d855454e59977a1cdbf522ea1db31"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.14.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "04cb8afbb01d855454e59977a1cdbf522ea1db31"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "3ba8aca90e17e5410b7e8b227c9f29256ac3e875"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.14.3"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.14.2-rc.1",
            "v0.14.2",
            "v0.14.1-rc.1",
            "v0.14.1",
            "v0.14.0-rc.1",
            "v0.14.0",
            "latest-commit-build",
            "v0.11.91",
            "v0.11.86",
            "v0.11.79",
            "v0.11.66",
            "v0.11.53",
            "v0.11.43",
            "v0.11.34",
            "v0.11.33",
            "v0.11.29",
            "v0.11.19",
            "v0.11.4",
            "v0.11",
            "v0.11rc",
            "v0.10.18",
            "v0.10.8",
            "v0.10",
            "v0.10rc",
            "v0.9.141",
            "v0.9.128",
            "v0.9.113",
            "v0.9.97",
            "v0.9.71",
            "v0.9.60",
            "v0.9.48",
            "v0.9.46",
            "v0.9.13",
            "v0.9.0",
            "v0.8.43",
            "v0.8.25",
            "v0.8.10",
            "v0.8.0",
            "v0.7.33",
            "v0.7.22",
            "v0.7.19",
            "v0.7.6",
            "v0.7.0",
            "v0.6.15",
            "v0.6.9",
            "v0.6.3",
            "v0.6.1",
            "v0.5.13",
            "v0.5.11",
            "v0.5.9",
            "v0.5.8",
            "v0.5.5",
            "v0.5.2",
            "v0.5.0",
            "v0.4.2",
            "v0.4.1",
            "v0.4.0",
            "v0.3.1",
            "v0.3.0",
            "v0.2.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52811.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.333428993Z",
      "provider": "osv",
      "references": [
        "https://github.com/gogs/gogs/releases/tag/v0.14.3",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52811.json",
        "https://github.com/gogs/gogs/security/advisories/GHSA-89mr-xqfv-758m",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-52811",
        "https://github.com/gogs/gogs/commit/04cb8afbb01d855454e59977a1cdbf522ea1db31",
        "https://github.com/gogs/gogs/pull/8332"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22",
          "CWE-59",
          "CWE-61"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52811.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-52811",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 488632,
  "published_at": "2026-06-24T20:31:38.233+00:00"
}