{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "zotregistry.dev/zot/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.1.15"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "zotregistry.dev/zot"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.3.0-20210831063041-c8779d9e87d9"
            },
            {
              "last_affected": "1.4.4-20251014054906-73eef25681af"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-31801"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-10T23:44:25Z",
    "nvd_published_at": "2026-03-10T21:16:49Z",
    "severity": "HIGH"
  },
  "details": "zot\u2019s dist-spec authorization middleware infers the required action for `PUT /v2/{name}/manifests/{reference}` as `create` by default, and only switches to `update` when the tag already exists and `reference != \"latest\"`.\n\nas a result, when `latest` already exists, a user who is allowed to `create` (but not allowed to `update`) can still pass the authorization check for an overwrite attempt of `latest`.\n\n## affected component\n\n- file: `pkg/api/authz.go` (`DistSpecAuthzHandler`)\n- condition: `slices.Contains(tags, reference) \u0026\u0026 reference != \"latest\"` (line 352 at the pinned commit)\n\n## severity\n\nHIGH\ncategory: CWE-863 (incorrect authorization)\n\nnote: impact depends on how a deployment uses `latest` (for example, if `latest` is treated as a protected or \u201cpush-once\u201d tag), and on how access control is provisioned (users with `create` but without `update`). the attached poc demonstrates a real overwrite of `latest` (tag digest changes) under a create-only policy.\n\n## steps to reproduce\n\n1. configure access control so user `attacker` has `create` but not `update` on a repository.\n2. ensure the repository has an existing tag named `latest`.\n3. attempt to push a new manifest to `/v2/acme/app/manifests/latest` (example repository name).\n4. observe that the authorization check is evaluated as `create` (not `update`) for `latest`, so the request passes authorization even though the tag already exists.\n\nthe attached poc demonstrates this deterministically with `canonical.log` and `control.log` markers.\n\n## expected vs actual\n\n- expected: overwriting an existing tag should require `update` permission, including `latest` (or `latest` should be explicitly documented as exempt).\n- actual: when `reference==\"latest\"` and the tag exists, the middleware keeps the action as `create` instead of switching to `update`.\n\n## security impact\n\nthis can break least-privilege expectations in deployments that rely on the `create` vs `update` split to prevent tag overwrites (for example, \u201cpush-once\u201d policies). if `latest` is used as a high-trust tag in ci/cd, this can create supply-chain risk because a create-only principal can overwrite an existing `latest` tag while other existing tags correctly require `update`.\n\n## suggested fix\n\nremove the special-case exemption for `latest` when determining whether an existing tag requires `update` permission (treat `latest` the same as other tags), or document and enforce an explicit policy rule for `latest`.\n\n## notes / rationale\n\n- oci distribution spec does not define a standard authorization model; this report is about zot\u2019s own create vs update semantics and the observable behavior in `DistSpecAuthzHandler`.\n- zot documentation describes immutable tags as being enforceable via authorization policies (create-only \u201cpush once\u201d, update disallowed). if `latest` is exempt, this control does not apply to `latest` unless documented otherwise.\n\n[addendum.md](https://github.com/user-attachments/files/24986139/addendum.md)\n[poc.zip](https://github.com/user-attachments/files/24986140/poc.zip)\n[PR_DESCRIPTION.md](https://github.com/user-attachments/files/24986141/PR_DESCRIPTION.md)\n[RUNNABLE_POC.md](https://github.com/user-attachments/files/24986142/RUNNABLE_POC.md)",
  "id": "GHSA-85jx-fm8m-x8c6",
  "modified": "2026-03-10T23:44:25Z",
  "published": "2026-03-10T23:44:25Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/project-zot/zot/security/advisories/GHSA-85jx-fm8m-x8c6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31801"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/project-zot/zot"
    },
    {
      "type": "WEB",
      "url": "https://github.com/project-zot/zot/releases/tag/v2.1.15"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "zot\u2019s create-only policy allows overwrite attempts of existing latest tag (update permission not required)"
}