Vulnerability-Lookup

GHSA-25GQ-J9JX-43PG

Vulnerability from github – Published: 2026-07-21 20:18 – Updated: 2026-07-21 20:18

Summary

Gitea: Release attachment extension allowlist bypass via web release edit form (variant of CVE-2025-68939)

Details

Summary

The web handler EditReleasePost (routers/web/repo/release.go) reads form fields with prefix attachment-edit-{uuid} into a map[uuid]newName, passes that map to release_service.UpdateRelease, which writes the new name to the database via repo_model.UpdateAttachmentByUUID WITHOUT calling upload.Verify against setting.Repository.Release.AllowedTypes. The parent CVE-2025-68939 fix (PR #32151) added the equivalent upload.Verify call on the API edit endpoints via attachment_service.UpdateAttachment. The web release edit path was not updated.

A user with repository write permission can rename any existing release attachment to a name with a forbidden extension via the web release edit form, bypassing the operator-configured allowlist.

Details

Vulnerable code

routers/web/repo/release.go:597 EditReleasePost:

const editPrefix = "attachment-edit-"
editAttachments := make(map[string]string)
if setting.Attachment.Enabled {
    for k, v := range ctx.Req.Form {
        if strings.HasPrefix(k, editPrefix) {
            editAttachments[k[len(editPrefix):]] = v[0]
        }
    }
}
...
if err = release_service.UpdateRelease(ctx, ctx.Doer, ctx.Repo.GitRepo,
    rel, addAttachmentUUIDs, delAttachmentUUIDs, editAttachments); err != nil {
    ctx.ServerError("UpdateRelease", err)
    return
}

services/release/release.go:321 -- the unvalidated write:

for uuid, newName := range editAttachments {
    if !deletedUUIDs.Contains(uuid) {
        if err = repo_model.UpdateAttachmentByUUID(ctx, &repo_model.Attachment{
            UUID: uuid,
            Name: newName,
        }, "name"); err != nil {
            return err
        }
    }
}

No upload.Verify(nil, newName, setting.Repository.Release.AllowedTypes) before the database write.

Comparison: the parent fix on the API path

routers/api/v1/repo/release_attachment.go:341 (patched in PR #32151):

if err := attachment_service.UpdateAttachment(ctx,
        setting.Repository.Release.AllowedTypes, attach); err != nil {
    if upload.IsErrFileTypeForbidden(err) {
        ctx.Error(http.StatusUnprocessableEntity, "", err)
        return
    }
    ctx.Error(http.StatusInternalServerError, "UpdateAttachment", attach)
    return
}

Delegates to:

// services/attachment/attachment.go:96
func UpdateAttachment(ctx context.Context, allowedTypes string, attach *repo_model.Attachment) error {
    if err := upload.Verify(nil, attach.Name, allowedTypes); err != nil {
        return err
    }
    return repo_model.UpdateAttachment(ctx, attach)
}

The API path goes through attachment_service.UpdateAttachment which calls upload.Verify(nil, attach.Name, allowedTypes). The web path bypasses this entirely.

Proof of Concept

Tested live against: * Gitea v1.26.1 community edition, Linux amd64, SQLite, Go 1.26.2 * app.ini includes [repository.release] ALLOWED_TYPES = .zip,.tar.gz * Two users: admin (superuser, created via gitea admin user create --admin), bob (regular, repo owner of bob/test-repo)

Step 1: bob creates release v0.1 and uploads innocent.zip (allowlist compliant) via the API.

Step 2: Sanity. The patched API edit endpoint rejects a rename to a forbidden extension.

PATCH /api/v1/repos/bob/test-repo/releases/1/assets/1 HTTP/1.1
Authorization: token <bob_token>
Content-Type: application/json

{"name":"evil.exe"}

Response: HTTP 422 -- "This file cannot be uploaded or modified due to a forbidden file extension or type." (parent CVE-2025-68939 fix in action).

Step 3: The attack. The web release edit form does NOT enforce the allowlist.

POST /bob/test-repo/releases/edit/v0.1 HTTP/1.1
Cookie: i_like_gitea=<session>; lang=en-US
Content-Type: application/x-www-form-urlencoded

tag_name=v0.1
&tag_target=main
&title=rename+payload
&content=
&attachment-edit-<existing_attachment_uuid>=evil.exe

Response: HTTP 303 -> /bob/test-repo/releases. The form is accepted with no validation error.

Step 4: Verify.

GET /api/v1/repos/bob/test-repo/releases/1/assets/1 HTTP/1.1

Response includes "name": "evil.exe". The download link /attachments/<uuid> now serves the file under the forbidden extension.

A self contained Python PoC ships with this advisory: GITEA-R007_release_edit_extension_bypass.py. End to end run:

GITEA-R007_release_edit_extension_bypass.py

[+] Logged in as bob
[+] Pre-attack attachment name: 'innocent2.zip'
[+] API endpoint correctly rejects rename: HTTP 422 (parent CVE-2025-68939 fix)
[+] POST release edit: HTTP 303 -> /bob/test-repo/releases
[+] Post-attack attachment name: 'pwn.exe'

[!!!] CONFIRMED: web release edit bypasses Release.AllowedTypes allowlist.

Impact

Same impact class as the parent CVE-2025-68939 (HIGH, CVSS 8.2):

Pre-condition: operator has set Repository.Release.AllowedTypes to a non-empty allowlist (a reasonable hardening posture when restricting release uploads).
Threat actor: user holding repository write permission. In most Gitea deployments this is the repo owner, organization members, or invited collaborators.
Effect: bypass the allowlist; an attachment uploaded under an allowed extension is renamed to a forbidden extension (.exe, .html, .svg, .js, ...) and served by Gitea under that name.
Practical impact:
Distribute malware files (e.g., .exe, .dmg, .msi, .apk) masquerading as a tagged release attachment
If Gitea serves attachments with inline rendering (HTML, SVG), the renamed file hosts stored XSS against the Gitea origin
Operator hardening intent (the allowlist) is silently defeated, with no audit trail beyond the regular release-edit event

Suggested remediation

Mirror the parent CVE-2025-68939 fix into the web release edit path. In services/release/release.go UpdateRelease, verify each new name against the configured allowlist before persisting:

import (
    "code.gitea.io/gitea/modules/setting"
    "code.gitea.io/gitea/services/context/upload"
)

// inside UpdateRelease, replace the editAttachments loop:
for uuid, newName := range editAttachments {
    if deletedUUIDs.Contains(uuid) {
        continue
    }
    if err := upload.Verify(nil, newName, setting.Repository.Release.AllowedTypes); err != nil {
        return err
    }
    if err = repo_model.UpdateAttachmentByUUID(ctx, &repo_model.Attachment{
        UUID: uuid,
        Name: newName,
    }, "name"); err != nil {
        return err
    }
}

The web handler EditReleasePost should map IsErrFileTypeForbidden to a 422 response (or equivalent flash error and form re-render) to match the API behavior.

Alternative: refactor attachment_service.UpdateAttachment to accept a UUID (or expose a UpdateAttachmentByUUID variant in the service layer) and have the release service call that instead of the raw model function.

Workaround for operators (no Gitea change required)

Until a patched release lands, operators can mitigate by either:

Removing the Repository.Release.AllowedTypes allowlist (accept any extension) -- this eliminates the bypass but also removes the defense, so it is only a holding move.
Putting Gitea behind a reverse proxy that rewrites or strips suspicious attachment-edit-* form fields on POST to /<owner>/<repo>/releases/edit/* -- viable but operationally fragile.
Restricting who has Write permission on repositories with a configured release allowlist -- in single-tenant deployments this may be acceptable.

A vendor patch is the right answer; the workarounds above are stopgaps.

Credit

Jose Rivas (bl4cksku111.com)

References

Parent advisory: https://github.com/advisories/GHSA-263q-5cv3-xq9g (CVE-2025-68939)
Parent fix: PR https://github.com/go-gitea/gitea/pull/32151 (commit 7adc4717ec)
CWE-424: https://cwe.mitre.org/data/definitions/424.html
CWE-434: https://cwe.mitre.org/data/definitions/434.html

Severity

6.5 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "code.gitea.io/gitea"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.27.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-58428"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-424",
      "CWE-434"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-21T20:18:44Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nThe web handler `EditReleasePost` (`routers/web/repo/release.go`) reads form fields with prefix `attachment-edit-{uuid}` into a `map[uuid]newName`, passes that map to `release_service.UpdateRelease`, which writes the new name to the database via `repo_model.UpdateAttachmentByUUID` WITHOUT calling `upload.Verify` against `setting.Repository.Release.AllowedTypes`. The parent CVE-2025-68939 fix (PR #32151) added the equivalent `upload.Verify` call on the API edit endpoints via `attachment_service.UpdateAttachment`. The web release edit path was not updated.\n\nA user with repository write permission can rename any existing release attachment to a name with a forbidden extension via the web release edit form, bypassing the operator-configured allowlist.\n\n## Details\n\n### Vulnerable code\n\n`routers/web/repo/release.go:597` `EditReleasePost`:\n\n```go\nconst editPrefix = \"attachment-edit-\"\neditAttachments := make(map[string]string)\nif setting.Attachment.Enabled {\n    for k, v := range ctx.Req.Form {\n        if strings.HasPrefix(k, editPrefix) {\n            editAttachments[k[len(editPrefix):]] = v[0]\n        }\n    }\n}\n...\nif err = release_service.UpdateRelease(ctx, ctx.Doer, ctx.Repo.GitRepo,\n    rel, addAttachmentUUIDs, delAttachmentUUIDs, editAttachments); err != nil {\n    ctx.ServerError(\"UpdateRelease\", err)\n    return\n}\n```\n\n`services/release/release.go:321` -- the unvalidated write:\n\n```go\nfor uuid, newName := range editAttachments {\n    if !deletedUUIDs.Contains(uuid) {\n        if err = repo_model.UpdateAttachmentByUUID(ctx, \u0026repo_model.Attachment{\n            UUID: uuid,\n            Name: newName,\n        }, \"name\"); err != nil {\n            return err\n        }\n    }\n}\n```\n\nNo `upload.Verify(nil, newName, setting.Repository.Release.AllowedTypes)` before the database write.\n\n### Comparison: the parent fix on the API path\n\n`routers/api/v1/repo/release_attachment.go:341` (patched in PR #32151):\n\n```go\nif err := attachment_service.UpdateAttachment(ctx,\n        setting.Repository.Release.AllowedTypes, attach); err != nil {\n    if upload.IsErrFileTypeForbidden(err) {\n        ctx.Error(http.StatusUnprocessableEntity, \"\", err)\n        return\n    }\n    ctx.Error(http.StatusInternalServerError, \"UpdateAttachment\", attach)\n    return\n}\n```\n\nDelegates to:\n\n```go\n// services/attachment/attachment.go:96\nfunc UpdateAttachment(ctx context.Context, allowedTypes string, attach *repo_model.Attachment) error {\n    if err := upload.Verify(nil, attach.Name, allowedTypes); err != nil {\n        return err\n    }\n    return repo_model.UpdateAttachment(ctx, attach)\n}\n```\n\nThe API path goes through `attachment_service.UpdateAttachment` which calls `upload.Verify(nil, attach.Name, allowedTypes)`. The web path bypasses this entirely.\n\n## Proof of Concept\n\nTested live against:\n* Gitea `v1.26.1` community edition, Linux amd64, SQLite, Go 1.26.2\n* `app.ini` includes `[repository.release] ALLOWED_TYPES = .zip,.tar.gz`\n* Two users: `admin` (superuser, created via `gitea admin user create --admin`), `bob` (regular, repo owner of `bob/test-repo`)\n\n**Step 1**: bob creates release v0.1 and uploads `innocent.zip` (allowlist compliant) via the API.\n\n**Step 2**: Sanity. The patched API edit endpoint rejects a rename to a forbidden extension.\n\n```http\nPATCH /api/v1/repos/bob/test-repo/releases/1/assets/1 HTTP/1.1\nAuthorization: token \u003cbob_token\u003e\nContent-Type: application/json\n\n{\"name\":\"evil.exe\"}\n```\n\nResponse: `HTTP 422` -- \"This file cannot be uploaded or modified due to a forbidden file extension or type.\" (parent CVE-2025-68939 fix in action).\n\n**Step 3**: The attack. The web release edit form does NOT enforce the allowlist.\n\n```http\nPOST /bob/test-repo/releases/edit/v0.1 HTTP/1.1\nCookie: i_like_gitea=\u003csession\u003e; lang=en-US\nContent-Type: application/x-www-form-urlencoded\n\ntag_name=v0.1\n\u0026tag_target=main\n\u0026title=rename+payload\n\u0026content=\n\u0026attachment-edit-\u003cexisting_attachment_uuid\u003e=evil.exe\n```\n\nResponse: `HTTP 303 -\u003e /bob/test-repo/releases`. The form is accepted with no validation error.\n\n**Step 4**: Verify.\n\n```http\nGET /api/v1/repos/bob/test-repo/releases/1/assets/1 HTTP/1.1\n```\n\nResponse includes `\"name\": \"evil.exe\"`. The download link `/attachments/\u003cuuid\u003e` now serves the file under the forbidden extension.\n\nA self contained Python PoC ships with this advisory: `GITEA-R007_release_edit_extension_bypass.py`. End to end run:\n\n[GITEA-R007_release_edit_extension_bypass.py](https://github.com/user-attachments/files/27739265/GITEA-R007_release_edit_extension_bypass.py)\n\n```\n[+] Logged in as bob\n[+] Pre-attack attachment name: \u0027innocent2.zip\u0027\n[+] API endpoint correctly rejects rename: HTTP 422 (parent CVE-2025-68939 fix)\n[+] POST release edit: HTTP 303 -\u003e /bob/test-repo/releases\n[+] Post-attack attachment name: \u0027pwn.exe\u0027\n\n[!!!] CONFIRMED: web release edit bypasses Release.AllowedTypes allowlist.\n```\n\n## Impact\n\nSame impact class as the parent CVE-2025-68939 (HIGH, CVSS 8.2):\n\n* Pre-condition: operator has set `Repository.Release.AllowedTypes` to a non-empty allowlist (a reasonable hardening posture when restricting release uploads).\n* Threat actor: user holding repository write permission. In most Gitea deployments this is the repo owner, organization members, or invited collaborators.\n* Effect: bypass the allowlist; an attachment uploaded under an allowed extension is renamed to a forbidden extension (.exe, .html, .svg, .js, ...) and served by Gitea under that name.\n* Practical impact:\n  * Distribute malware files (e.g., `.exe`, `.dmg`, `.msi`, `.apk`) masquerading as a tagged release attachment\n  * If Gitea serves attachments with inline rendering (HTML, SVG), the renamed file hosts stored XSS against the Gitea origin\n  * Operator hardening intent (the allowlist) is silently defeated, with no audit trail beyond the regular release-edit event\n\n## Suggested remediation\n\nMirror the parent CVE-2025-68939 fix into the web release edit path. In `services/release/release.go UpdateRelease`, verify each new name against the configured allowlist before persisting:\n\n```go\nimport (\n    \"code.gitea.io/gitea/modules/setting\"\n    \"code.gitea.io/gitea/services/context/upload\"\n)\n\n// inside UpdateRelease, replace the editAttachments loop:\nfor uuid, newName := range editAttachments {\n    if deletedUUIDs.Contains(uuid) {\n        continue\n    }\n    if err := upload.Verify(nil, newName, setting.Repository.Release.AllowedTypes); err != nil {\n        return err\n    }\n    if err = repo_model.UpdateAttachmentByUUID(ctx, \u0026repo_model.Attachment{\n        UUID: uuid,\n        Name: newName,\n    }, \"name\"); err != nil {\n        return err\n    }\n}\n```\n\nThe web handler `EditReleasePost` should map `IsErrFileTypeForbidden` to a 422 response (or equivalent flash error and form re-render) to match the API behavior.\n\nAlternative: refactor `attachment_service.UpdateAttachment` to accept a UUID (or expose a `UpdateAttachmentByUUID` variant in the service layer) and have the release service call that instead of the raw model function.\n\n## Workaround for operators (no Gitea change required)\n\nUntil a patched release lands, operators can mitigate by either:\n\n1. Removing the `Repository.Release.AllowedTypes` allowlist (accept any extension) -- this eliminates the bypass but also removes the defense, so it is only a holding move.\n2. Putting Gitea behind a reverse proxy that rewrites or strips suspicious `attachment-edit-*` form fields on POST to `/\u003cowner\u003e/\u003crepo\u003e/releases/edit/*` -- viable but operationally fragile.\n3. Restricting who has Write permission on repositories with a configured release allowlist -- in single-tenant deployments this may be acceptable.\n\nA vendor patch is the right answer; the workarounds above are stopgaps.\n\n## Credit\n\nJose Rivas (bl4cksku111.com)\n\n## References\n\n* Parent advisory: https://github.com/advisories/GHSA-263q-5cv3-xq9g (CVE-2025-68939)\n* Parent fix: PR https://github.com/go-gitea/gitea/pull/32151 (commit `7adc4717ec`)\n* CWE-424: https://cwe.mitre.org/data/definitions/424.html\n* CWE-434: https://cwe.mitre.org/data/definitions/434.html",
  "id": "GHSA-25gq-j9jx-43pg",
  "modified": "2026-07-21T20:18:44Z",
  "published": "2026-07-21T20:18:44Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/security/advisories/GHSA-25gq-j9jx-43pg"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/pull/38406"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/pull/38426"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/commit/de4b8277e9cb576f2315fb03b5ab6478b42a1d31"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/commit/f69e15afe7496cc62e96dab244629c69eb31a7bf"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/go-gitea/gitea"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-gitea/gitea/releases/tag/v1.27.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Gitea: Release attachment extension allowlist bypass via web release edit form (variant of CVE-2025-68939)"
}

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.

Action not permitted

GHSA-25GQ-J9JX-43PG

Summary

Details

Vulnerable code

Comparison: the parent fix on the API path

Proof of Concept

Impact

Suggested remediation

Workaround for operators (no Gitea change required)

Credit

References

Tags

Sightings

Nomenclature