CVE-2026-39243

decompress before 4.2.2 allows arbitrary hardlink creation during archive extraction, enabling file read disclosure and file corruption. When processing hardlink entries (type === 'link'), the x.linkname field from the archive is passed directly to fs.link() without validation (index.js line 113). An attacker can craft an archive with a hardlink entry whose linkname is an absolute path to any file on the same filesystem. This creates a hardlink inside the extraction directory that shares the same inode as the target file, enabling both reading and overwriting the original file's content. Hardlinks are limited to files on the same filesystem and cannot target directories.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/kevva/decompress	Product
https://github.com/kevva/decompress/issues/113	Exploit Vendor Advisory
https://www.npmjs.com/package/decompress	Product
https://github.com/kevva/decompress/issues/113	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:decompress_project:decompress:*:*:*:*:*:node.js:*:*

History

No history.

Information

Published : 2026-07-09 22:17

Updated : 2026-07-13 12:57

NVD link : CVE-2026-39243

Mitre link : CVE-2026-39243

CVE.ORG link : CVE-2026-39243

JSON object : View

Products Affected

decompress_project

decompress

CWE

CWE-59

Improper Link Resolution Before File Access ('Link Following')

{"id": "CVE-2026-39243", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-39243", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-10T15:24:02.481203Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"vendor": "n/a", "product": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}]}], "published": "2026-07-09T22:17:04.113", "references": [{"url": "https://github.com/kevva/decompress", "tags": ["Product"], "source": "cve@mitre.org"}, {"url": "https://github.com/kevva/decompress/issues/113", "tags": ["Exploit", "Vendor Advisory"], "source": "cve@mitre.org"}, {"url": "https://www.npmjs.com/package/decompress", "tags": ["Product"], "source": "cve@mitre.org"}, {"url": "https://github.com/kevva/decompress/issues/113", "tags": ["Exploit", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-59"}]}], "descriptions": [{"lang": "en", "value": "decompress before 4.2.2 allows arbitrary hardlink creation during archive extraction, enabling file read disclosure and file corruption. When processing hardlink entries (type === 'link'), the x.linkname field from the archive is passed directly to fs.link() without validation (index.js line 113). An attacker can craft an archive with a hardlink entry whose linkname is an absolute path to any file on the same filesystem. This creates a hardlink inside the extraction directory that shares the same inode as the target file, enabling both reading and overwriting the original file's content. Hardlinks are limited to files on the same filesystem and cannot target directories."}], "lastModified": "2026-07-13T12:57:34.913", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:decompress_project:decompress:*:*:*:*:*:node.js:*:*", "vulnerable": true, "matchCriteriaId": "E8F446F1-2102-4B37-9373-9890272E6B79", "versionEndIncluding": "4.2.1"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}