Decompress: Archive extraction can create files and links outside of the target directory
Impact
When extracting an archive to a directory, a crafted archive can read or write files outside that directory. The flaw is in the code that writes the parsed entries, so it affects every format decompress handles: tar, tar.gz, tar.bz2, and zip by default, plus any others added through the plugins option.
A link (hardlink) or symlink entry is created without checking where its target points. A hardlink can be aimed at any file the running process can read; that file then appears inside the output directory and its contents are exposed. A symlink can point outside the output directory and redirect a later write.
The path containment check used a string prefix comparison (realPath.indexOf(outputPath) !== 0). Output /srv/out does not contain /srv/out-old, but the prefix comparison treats it as inside, so an entry can escape into a sibling directory whose name starts with the output directory name.
File modes were applied as mode & ~umask, which does not remove the setuid, setgid, or sticky bits. A crafted entry can create a setuid or setgid file. This matters when extraction runs as root, for example in CI, containers, or install scripts.
Any code that extracts archives from an untrusted or attacker-influenced source is affected. Archives are commonly downloaded before extraction, so this is reachable over the network in many setups.
Patches
Fixed in @xhmikosr/decompress 10.2.1 and 11.1.3. Link targets are now resolved and checked against the output directory, containment uses path.relative, and setuid, setgid, and sticky bits are removed.
The upstream decompress package is unmaintained, and all versions through its last release (4.2.1) have the same flaws. There is no upstream fix. Migrate to @xhmikosr/decompress 11.1.3 or later.
Workarounds
Extract only archives you trust. Run extraction as a non-root user so the mode issue cannot create a privileged file. After extracting, reject any symlink or hardlink that points outside the target and any file with unexpected mode bits.
Resources
- Related prior issue in the upstream project this package forks: CVE-2020-12265 / GHSA-qgfr-5hqp-vrw9
- Fix commits and releases:
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | decompress | <= 4.2.1 | no fix |
| npm package | @xhmikosr/decompress | < 10.2.1, >= 11.0.0, < 11.1.3 | 10.2.1, 11.1.3 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-22, CWE-59, CWE-732- Platform
- npm
- Package
decompress, @xhmikosr/decompress- Disclosed
- 06.07.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-mp2f-45pm-3cg9 - CC BY 4.0
Vulnerability history: decompress
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 5
- First → latest
- 09.2020 09.2026
- Without a fix
- 4
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
- Medium 2
Disclosures per year
- 2020: 1
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 4
-
Decompress: Archive extraction can create files and links outside of the target directory this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.