{"id":"CVE-2026-22864","aliases":["EUVD-2026-2935","GHSA-m3c4-prhw-mrx6","JLSEC-2026-115"],"status":"published","title":"Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass","description":"Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.","severity":{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00672,"percentile":0.52416,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-77"],"published":"2026-01-15T22:58:52Z","modified":"2026-10-28T02:30:30Z","fixes":[{"ecosystem":"crates.io","package":"deno","fixed_in":["2.5.6"],"sources":["ghsa","osv"]},{"ecosystem":"Julia","package":"Deno_jll","fixed_in":["2.6.3+0"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"deno","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.6"}]}]},{"source":"osv","ecosystem":"crates.io","package":"deno","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.5.6"}]}]},{"source":"osv","ecosystem":"Julia","package":"Deno_jll","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.6.3+0"}]}]}],"products":[{"vendor":"deno","product":"deno"},{"vendor":"denoland","product":"deno"}],"references":[{"url":"https://github.com/denoland/deno/security/advisories/GHSA-m3c4-prhw-mrx6","tags":["x_refsource_CONFIRM","Exploit","Vendor Advisory","advisory","web"]},{"url":"https://github.com/denoland/deno/releases/tag/v2.5.6","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-22864","tags":["advisory","web"]},{"url":"https://github.com/advisories/GHSA-m3c4-prhw-mrx6","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/22xxx/CVE-2026-22864.json","tags":["advisory"]},{"url":"https://github.com/denoland/deno","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-22864","title":"Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass","description":"Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.","status":"published","published":"2026-01-15T22:58:52.463Z","modified":"2026-01-16T17:16:02.143Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-77"],"updated_at":"2026-11-02T13:39:05.585774Z"}],"euvd":[{"id":"EUVD-2026-2935","description":"Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.","status":"published","published":"2026-01-15T22:58:52Z","modified":"2026-01-16T17:16:02Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T19:48:50.882066Z"}],"ghsa":[{"id":"GHSA-m3c4-prhw-mrx6","title":"Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass","description":"### Summary\nA prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched `.bat` or `.cmd`. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example `.BAT, .Bat`, etc.).\n\n### POC\n```javascript\nconst command = new Deno.Command('./test.BAT', {\n  args: ['\u0026calc.exe'],\n});\nconst child = command.spawn();\n```\nThis causes `calc.exe` to be launched; see the attached screenshot for evidence.\n\n**Patched in `CVE-2025-61787` — prevents execution of `.bat` and `.cmd` files:**\n![photo_2025-10-10 02 27 23](https://github.com/user-attachments/assets/43df25e2-e2e1-48aa-8060-cb0a22637f1f)\n\n**Bypass of the patched vulnerability:**\n![photo_2025-10-10 02 27 25](https://github.com/user-attachments/assets/2be1afb4-84a1-4883-8e18-6a174fdd3615)\n\n\n### Impact\nThe script launches calc.exe on Windows, demonstrating that passing user-controlled arguments to a spawned batch script can result in command-line injection.\n\n### Mitigation\n\nUsers should update to Deno v2.5.6 or newer.","status":"published","published":"2026-01-16T15:49:38Z","modified":"2026-08-28T09:52:28Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-77"],"updated_at":"2026-11-02T14:41:07.031507Z"}],"nvd":[{"id":"CVE-2026-22864","description":"Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.","status":"published","published":"2026-01-15T23:15:51.937Z","modified":"2026-06-17T10:20:31.7Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"}],"cwes":["CWE-77"],"updated_at":"2026-11-02T14:12:04.066712Z"}],"osv":[{"id":"CVE-2026-22864","title":"Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass","description":"Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.","status":"published","published":"2026-01-15T22:58:52.463Z","modified":"2026-10-28T02:30:30.402118851Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-77"],"updated_at":"2026-11-02T15:44:58.749922Z"},{"id":"GHSA-m3c4-prhw-mrx6","title":"Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass","description":"### Summary\nA prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched `.bat` or `.cmd`. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example `.BAT, .Bat`, etc.).\n\n### POC\n```javascript\nconst command = new Deno.Command('./test.BAT', {\n  args: ['\u0026calc.exe'],\n});\nconst child = command.spawn();\n```\nThis causes `calc.exe` to be launched; see the attached screenshot for evidence.\n\n**Patched in `CVE-2025-61787` — prevents execution of `.bat` and `.cmd` files:**\n![photo_2025-10-10 02 27 23](https://github.com/user-attachments/assets/43df25e2-e2e1-48aa-8060-cb0a22637f1f)\n\n**Bypass of the patched vulnerability:**\n![photo_2025-10-10 02 27 25](https://github.com/user-attachments/assets/2be1afb4-84a1-4883-8e18-6a174fdd3615)\n\n\n### Impact\nThe script launches calc.exe on Windows, demonstrating that passing user-controlled arguments to a spawned batch script can result in command-line injection.\n\n### Mitigation\n\nUsers should update to Deno v2.5.6 or newer.","status":"published","published":"2026-01-16T15:49:38Z","modified":"2026-02-03T03:17:23.271119Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-77"],"updated_at":"2026-11-02T15:46:51.10002Z"},{"id":"JLSEC-2026-115","title":"Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass","description":"### Summary\n\nA prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched `.bat` or `.cmd`. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example `.BAT, .Bat`, etc.).\n\n### POC\n\n```javascript\nconst command = new Deno.Command('./test.BAT', {\n  args: ['\u0026calc.exe'],\n});\nconst child = command.spawn();\n```\n\nThis causes `calc.exe` to be launched; see the attached screenshot for evidence.\n\n**Patched in `CVE-2025-61787` — prevents execution of `.bat` and `.cmd` files:**\n![photo_2025-10-10 02 27 23](https://github.com/user-attachments/assets/43df25e2-e2e1-48aa-8060-cb0a22637f1f)\n\n**Bypass of the patched vulnerability:**\n![photo_2025-10-10 02 27 25](https://github.com/user-attachments/assets/2be1afb4-84a1-4883-8e18-6a174fdd3615)\n\n### Impact\n\nThe script launches calc.exe on Windows, demonstrating that passing user-controlled arguments to a spawned batch script can result in command-line injection.\n\n### Mitigation\n\nUsers should update to Deno v2.5.6 or newer.","status":"published","published":"2026-04-14T13:10:46.494Z","modified":"2026-07-18T00:01:28.717630662Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:47:18.159338Z"}]}}