{"id":"GHSA-p9f5-h3rx-j5qw","summary":"Gogs Missing Authorization in Attachment Download","details":"## Summary\n\nIn Gogs 0.14.1, `GET /attachments/:uuid` returns the raw attachment file **without verifying whether the requester has view permission for the associated Issue/Comment/Release or the repository**.\nIn a test environment with `REQUIRE_SIGNIN_VIEW = false`, we confirmed that **an unauthenticated user can download attachments belonging to a private repository**.\n\n## Description\n\n`/attachments/:uuid` retrieves an attachment record solely by the UUID provided in the URL and returns the corresponding local file **without performing any authorization checks** against the attachment’s parent object (Issue/Comment/Release) or the repository it belongs to. As a result, even attachments under private repositories can be downloaded by an unauthenticated user (or a user without proper permissions) as long as the UUID is known.\n\nRelevant code (internal/cmd/web.go:306):\n\n```go\nm.Get(\"/attachments/:uuid\", func(c *context.Context) {\n\tattach, err := database.GetAttachmentByUUID(c.Params(\":uuid\"))\n\tif err != nil {\n\t\tc.NotFoundOrError(err, \"get attachment by UUID\")\n\t\treturn\n\t} else if !com.IsFile(attach.LocalPath()) {\n\t\tc.NotFound()\n\t\treturn\n\t}\n\n\tfr, err := os.Open(attach.LocalPath())\n\tif err != nil {\n\t\tc.Error(err, \"open attachment file\")\n\t\treturn\n\t}\n\tdefer fr.Close()\n\n\tc.Header().Set(\"Content-Security-Policy\", \"default-src 'none'; style-src 'unsafe-inline'; sandbox\")\n\tc.Header().Set(\"Cache-Control\", \"public,max-age=86400\")\n\tc.Header().Set(\"Content-Disposition\", fmt.Sprintf(`inline; filename=\"%s\"`, attach.Name))\n\n\tif _, err = io.Copy(c.Resp, fr); err != nil {\n\t\tc.Error(err, \"copy from file to response\")\n\t\treturn\n\t}\n})\n```\n\nThe UUID lookup itself also performs **no validation tied to repository visibility or user permissions**. Authorization is not enforced at this layer.\n\nRelevant code (internal/database/attachment.go:124):\n\n```go\n// GetAttachmentByUUID returns attachment by given UUID.\nfunc GetAttachmentByUUID(uuid string) (*Attachment, error) {\n\treturn getAttachmentByUUID(x, uuid)\n}\n```\n\n## Preconditions\n\n* The attacker knows the target attachment’s UUID (i.e., the attachment URL).\n* For unauthenticated exploitation: `[auth] REQUIRE_SIGNIN_VIEW = false`.\n* Even when `REQUIRE_SIGNIN_VIEW = true`, exploitation may still be possible because the handler does not check repository-level permissions; a user who can log in but lacks access to the target repository may still retrieve the attachment.\n\n## Steps to Reproduce\n\n1. Log in as an administrator and create a private repository, e.g. `myadmin/idor-attach-1770724346-1a13bb`.\n2. Add an attachment to an Issue in that repository and note the attachment UUID\n   (example UUID used during testing: `f06d90f8-5b62-4c10-ac8d-f11fdf870b57`).\n3. Log out and access the following as an unauthenticated user:\n\n* The repository page → 404 Not Found\n\u003cimg width=\"1702\" height=\"758\" alt=\"image\" src=\"https://github.com/user-attachments/assets/8fdb1d92-cfc3-4ef8-977e-60ec13f792df\" /\u003e\n\n* The Issue page under that repository → 404 Not Found\n\u003cimg width=\"1983\" height=\"546\" alt=\"image\" src=\"https://github.com/user-attachments/assets/c44c5e69-8ca2-4ea6-a071-62302b7e896f\" /\u003e\n\n* `GET /attachments/\u003cuuid\u003e` → **the attachment file is successfully downloaded**\n\u003cimg width=\"2007\" height=\"378\" alt=\"image\" src=\"https://github.com/user-attachments/assets/23950ac6-6b3a-42f8-a06b-b9e0cf508d24\" /\u003e\n\n\n\n## Minimum Required Privileges\n\n* `REQUIRE_SIGNIN_VIEW = false`: none (works without authentication).\n* `REQUIRE_SIGNIN_VIEW = true`: only the ability to log in (repository view permission is not required in practice).\n\n## Impact\n\n* Confidential information attached to private repositories or restricted Issues/Releases may be disclosed.\n\n  * Examples include credentials, cryptographic keys, personal data, internal documents, or unpublished source code fragments.\n* While the severity depends on the attachment contents, attachments frequently contain sensitive data, making the potential impact high.","aliases":["CVE-2026-52799","GO-2026-5536"],"modified":"2026-07-21T13:45:21.725049239Z","published":"2026-06-22T23:59:03Z","database_specific":{"github_reviewed_at":"2026-06-22T23:59:03Z","nvd_published_at":"2026-06-24T21:16:55Z","cwe_ids":["CWE-639","CWE-862"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/gogs/gogs/security/advisories/GHSA-p9f5-h3rx-j5qw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52799"},{"type":"WEB","url":"https://github.com/gogs/gogs/pull/8320"},{"type":"WEB","url":"https://github.com/gogs/gogs/commit/d3ca23f9f33d5710472a775d6dcd3a7bb128bb05"},{"type":"PACKAGE","url":"https://github.com/gogs/gogs"},{"type":"WEB","url":"https://github.com/gogs/gogs/releases/tag/v0.14.3"}],"affected":[{"package":{"name":"gogs.io/gogs","ecosystem":"Go","purl":"pkg:golang/gogs.io/gogs"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.14.3"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 0.14.2","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-p9f5-h3rx-j5qw/GHSA-p9f5-h3rx-j5qw.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}