Bug 2498840 (CVE-2026-39246)

Summary: CVE-2026-39246 decompress: decompress: arbitrary symlink creation during archive extraction leads to information disclosure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: aschwart, aszczucz, boliveir, drichtar, gparvin, mposolda, pjindal, rhaigner, rmartinc, ssilvert, sthorger, vmuzikar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the decompress package for Node.js. The package creates symlinks from archive entries during extraction without validating the link target against the output directory, because the existing containment check only applies to regular file entries. An attacker who can supply a crafted archive for extraction can create a symlink pointing outside the output directory (for example to /etc/passwd), leading to disclosure of arbitrary files readable by the extracting process when the application later reads the extracted content.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2499745, 2499747    
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Description OSIDB Bzimport 2026-07-09 22:03:28 UTC 
decompress before 4.2.2 allows arbitrary symlink creation during archive extraction. When processing symlink entries (type === 'symlink'), the x.linkname field from the archive is passed directly to fs.symlink() without validation (index.js line 121). The preventWritingThroughSymlink check on line 98 only applies to file entries, not symlink creation. An attacker can craft an archive with symlink entries pointing to sensitive files outside the extraction directory (e.g., /etc/passwd), enabling information disclosure when the application reads the extracted contents.