{"answers":{"affected":"2 open source packages ship an affected version, including vm2.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100721 exists.","fix":"Upgrade vm2 to 3.12.2 or later.","what":"CVE-2026-100721 is a critical authentication bypass vulnerability in patriksimek vm2, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-100721 and fix it if it is affected.\n\nWhat it is: CVE-2026-100721 is a critical authentication bypass vulnerability in patriksimek vm2, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100721 exists.\n\nAffected packages and fixed versions:\n- vm2 (npm): affected all versions; fixed in 3.12.2\n- vm2 (npm): affected all versions; fixed in 3.12.2\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-100721/ (Markdown: https://insights.sbomify.com/CVE-2026-100721/index.md)","id":"CVE-2026-100721","markdown":"https://insights.sbomify.com/CVE-2026-100721/index.md","name":"CVE-2026-100721","record":{"aliases":["CLEANSTART-2026-CN31177","CLSA-2026-1791887363","CLSA-2026-1791888008","ECHO-923f-7c77-29c1","GHSA-5h3f-q97h-ccvc","MINI-52gv-5c3m-r2x9","ROOT-APP-NPM-CVE-2026-100721"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution","privilege_escalation"],"network_reachable":"yes","non_default_config":true,"product_category":"Node.js sandbox library","requires_auth":"none","summary":"Attackers can escape the vm2 sandbox and execute arbitrary code in the host process if a custom resolver is configured without proper path boundaries.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[],"cvss":{"score":9.5,"severity":"critical","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","version":"4.0"},"cwes":[{"id":"CWE-863","name":"Incorrect Authorization"}],"description":"vm2 before 3.12.2 contains an authorization bypass in the NodeVM external-module resolver. When an embedder configures `require.external` with a custom resolver (and `context: 'host'`), `LegacyResolver.customResolve` in lib/resolver-compat.js records the resolved module directory in `this.externals` as `new RegExp('^' + escapeRegExp(resolvedPath))`, without requiring a path separator or end-of-string boundary. Untrusted guest code can therefore require the allowlisted module (e.g. `foo`) and then require the absolute path of a non-allowlisted sibling whose path merely shares the resolved prefix (e.g. `.../node_modules/foo2/index.js`); the sibling passes `isPathAllowedForModule` and is loaded through `hostRequire`, so its top-level code runs in the host process before the exports are wrapped with `vm.readonly`, resulting in a sandbox escape and arbitrary code execution in the host context.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":"2026-09-28","github_poc":1,"max_poc_stars":0,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-09-28T09:45:48Z","kind":"github_poc","ref":"https://github.com/murrez/CVE-2026-100721","stars":0,"title":"CVE-2026-100721 PoC: vm2 \u003c3.12.2 NodeVM external allowlist bypass → sandbox escape / host RCE. Local Node lab (evil-left-pad), remote sandbox API mass exploit, colorful CLI. PoCbit — https://pocbit.org/pocs/cve-2026-100721"}],"tier":"weaponised"},"has_fix":true,"headline":"vm2 before 3.12.2 Authorization Bypass via Custom Resolver","id":"CVE-2026-100721","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":2,"n_references":5,"next":{"headline":"vm2 before 3.12.2 Host Process Termination via Construct Trap","id":"CVE-2026-100722"},"packages":[{"ecosystem":"npm","fixed":["3.12.2"],"introduced":["0"],"last_affected":[],"package":"vm2","purl":null,"source":"GHSA-5h3f-q97h-ccvc"},{"ecosystem":"npm","fixed":["3.12.2"],"introduced":["0"],"last_affected":[],"package":"vm2","purl":"pkg:npm/vm2","source":"GHSA-5h3f-q97h-ccvc"}],"prev":{"headline":"Froxlor before 2.3.12 Stored XSS via SSL certificate issuer","id":"CVE-2026-100720"},"products":["vm2"],"published":"2026-09-27","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-09-28","vendors":["patriksimek"]},"summary":"Attackers can escape the vm2 sandbox and execute arbitrary code in the host process if a custom resolver is configured without proper path boundaries.","url":"https://insights.sbomify.com/CVE-2026-100721/"}