{"id":"GHSA-83pc-3rw9-qpwj","revision":"8010f8b34f234670ba550af58b3378f4","records":[{"revision":"8010f8b34f234670ba550af58b3378f4","observedAt":"2026-10-24T13:19:54.901+00:00","statement":{"source":"osv","id":"GHSA-83pc-3rw9-qpwj","aliases":["CVE-2026-49860"],"title":"Deno: WebSocket API sandbox bypass via missing post-DNS check","description":"## Summary\n\nWhen a WebSocket connection was opened, Deno checked the destination hostname\nagainst `--deny-net` rules but did not re-check the IP addresses that hostname\nresolved to. An attacker-controlled script could use a specially crafted domain\nname that passes the hostname check yet resolves to a denied IP, bypassing the\nnetwork restriction entirely.\n\n## Impact\n\nCode running under `--deny-net` could connect to hosts that the user intended\nto block. In practice this means network isolation rules — for example,\nblocking access to `localhost` or internal services — could be silently\ncircumvented by a malicious or compromised dependency.\n\n`Deno.connect` and `fetch()` were not affected by this specific issue (a\ncompanion advisory covers `fetch()`).\n\n## Who is affected\n\nUsers who:\n\n- run untrusted or third-party code with `deno run`, and\n- rely on `--deny-net` to restrict which hosts that code can reach.\n\nIf you do not use `--deny-net`, or if you only run fully trusted code, you are\nnot affected.\n\n## Workaround\n\nNo workaround is available short of upgrading. If upgrading immediately is not\npossible, avoid granting `--allow-net` to untrusted code that also has\n`--deny-net` restrictions you depend on for security.","state":0,"publishedAt":"2026-06-16T19:04:07+00:00","modifiedAt":"2026-07-20T21:15:27.2536272+00:00","affected":[{"ecosystem":"crates.io","name":"deno","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"2.8.1"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/denoland/deno/security/advisories/GHSA-83pc-3rw9-qpwj","https://nvd.nist.gov/vuln/detail/CVE-2026-49860","https://github.com/denoland/deno"],"sourceUrl":"https://github.com/advisories/GHSA-83pc-3rw9-qpwj","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-83pc-3rw9-qpwj","identifiers":["GHSA-83pc-3rw9-qpwj","CVE-2026-49860"]},"retained":false,"historicalAffected":[]}],"coverage":[]}