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@xhmikosr/decompress: Path traversal via symlink chain

Critical severity GitHub Reviewed Published Sep 15, 2026 in XhmikosR/decompress • Updated Sep 29, 2026

Package

npm @xhmikosr/decompress (npm)

Affected versions

>= 11.0.0, <= 11.1.3
<= 10.2.1

Patched versions

11.1.4
10.2.2
npm decompress (npm)
<= 4.2.1
None

Description

Impact

When extracting an untrusted archive with the default decompress(input, output) API, a crafted archive containing a chain of symlink entries can make a later entry resolve outside the output directory. The lexical containment checks pass, but the kernel follows the planted symlinks to a path outside output, letting an attacker write (and read) files outside the intended extraction directory. Overwriting startup scripts or configuration can lead to remote code execution.

This is a bypass of the hardening in GHSA-mp2f-45pm-3cg9. Any application that extracts attacker-controlled archives is affected.

Patches

Fixed in 11.1.4 (latest) and backported to 10.2.2 (release-v10 dist-tag). Upgrade to one of these.

The unmaintained upstream decompress package shares this flaw and will not be patched. Migrate to @xhmikosr/decompress@11.1.4 (or @10.2.2).

Workarounds

None. Do not extract untrusted archives on affected versions. If you cannot upgrade, validate entries out of band and reject any whose resolved path escapes the target directory.

References

@XhmikosR XhmikosR published to XhmikosR/decompress Sep 15, 2026
Published by the National Vulnerability Database Sep 28, 2026
Published to the GitHub Advisory Database Sep 29, 2026
Reviewed Sep 29, 2026
Last updated Sep 29, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(56th percentile)

Weaknesses

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Learn more on MITRE.

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

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. Learn more on MITRE.

CVE ID

CVE-2026-101894

GHSA ID

GHSA-hrh2-vp3x-79xf

Source code

Credits

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