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PatchSiren cyber security CVE debrief

CVE-2026-39246 kevva CVE debrief

The decompress package before version 4.2.2 allows for arbitrary symlink creation during archive extraction. This vulnerability arises from the lack of validation when processing symlink entries in an archive. Specifically, the x.linkname field from the archive is directly passed to fs.symlink() without proper checks. This oversight enables an attacker to craft an archive with symlinks pointing to sensitive files outside the extraction directory, potentially leading to information disclosure when the application reads the extracted contents.

Vendor
kevva
Product
decompress
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-09
Original CVE updated
2026-07-13
Advisory published
2026-07-09
Advisory updated
2026-07-13

Who should care

Developers and administrators using the decompress package in their applications, especially those handling archive extractions, should be aware of this vulnerability. Given the high CVSS score of 7.5, this issue is considered serious and requires immediate attention to prevent potential exploitation.

Technical summary

The decompress package, used for extracting archives, has a vulnerability that allows for the creation of arbitrary symlinks during extraction. This is due to the direct use of the x.linkname field from symlink entries in the archive without validation, bypassing the preventWritingThroughSymlink check that only applies to file entries. An attacker could exploit this by crafting an archive with symlinks to sensitive files (e.g., /etc/passwd), leading to information disclosure when the extracted contents are read.

Defensive priority

High priority should be given to updating the decompress package to version 4.2.2 or later. Developers should also review their applications' handling of archive extractions and consider implementing additional validation and monitoring to detect and prevent exploitation attempts.

Recommended defensive actions

  • Update the decompress package to version 4.2.2 or later.
  • Review and validate archive extraction processes in applications.
  • Implement monitoring to detect exploitation attempts.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record was published on 2026-07-09T22:17:04.370Z and was last modified on 2026-07-10T18:52:44.960Z. The NVD entry is currently Undergoing Analysis. The vulnerability has a CVSS score of 7.5, indicating high severity.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-39246 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-39246

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-39246 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-39246

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.