{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.7.0-beta.9"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5e8e9180038895ad793b7bbe9fd095fa41d48459"
            }
          ],
          "repo": "https://github.com/lemmynet/activitypub-federation-rust",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-918"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33693.json"
  },
  "details": "Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the `v4_is_invalid()` function in `activitypub-federation-rust` (`src/utils.rs`) does not check for `Ipv4Addr::UNSPECIFIED` (0.0.0.0). An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the SSRF protection introduced by the fix for CVE-2025-25194 (GHSA-7723-35v7-qcxw), and reach localhost services on the target server. Version 0.7.0-beta.9 patches the issue.",
  "id": "CVE-2026-33693",
  "modified": "2026-04-01T23:08:01.654139686Z",
  "published": "2026-03-27T00:03:35.946Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33693.json"
    },
    {
      "type": "FIX",
      "url": "https://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755240b7f55d4a5b7665351599"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-7723-35v7-qcxw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33693"
    }
  ],
  "related": [
    "GHSA-q537-8fr5-cw35",
    "GHSA-7723-35v7-qcxw"
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Lemmy's Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid()"
}