CVE-2026-53486

The decompress package for Node.js extracts archives. Prior to 10.2.1 and 11.1.3, archive extraction can create files and links outside the target directory. When extracting an archive to a directory, a crafted archive can read or write files outside that directory because hardlink and symlink entries are created without checking where targets point, path containment used a string prefix comparison, and file modes failed to remove setuid, setgid, or sticky bits. This issue is fixed in @xhmikosr/decompress versions 10.2.1 and 11.1.3.

The decompress package for Node.js extracts archives. Prior to 10.2.1 and 11.1.3, archive extraction can create files and links outside the target directory. When extracting an archive to a directory, a crafted archive can read or write files outside that directory because hardlink and symlink entries are created without checking where targets point, path containment used a string prefix comparison, and file modes failed to remove setuid, setgid, or sticky bits. This issue is fixed in @xhmikosr/decompress versions 10.2.1 and 11.1.3.

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:
  • https://github.com/XhmikosR/decompress/releases/tag/v10.2.1
  • https://github.com/XhmikosR/decompress/releases/tag/v11.1.3
  • https://github.com/XhmikosR/decompress/commit/aca5aac
  • https://github.com/XhmikosR/decompress/commit/281cefa
  • https://github.com/XhmikosR/decompress/commit/60b5299

The decompress package for Node.js extracts archives. Prior to 10.2.1 and 11.1.3, archive extraction can create files and links outside the target directory. When extracting an archive to a directory, a crafted archive can read or write files outside that directory because hardlink and symlink entries are created without checking where targets point, path containment used a string prefix comparison, and file modes failed to remove setuid, setgid, or sticky bits. This issue is fixed in @xhmikosr/decompress versions 10.2.1 and 11.1.3.

The decompress package for Node.js extracts archives. Prior to 10.2.1 and 11.1.3, archive extraction can create files and links outside the target directory. When extracting an archive to a directory, a crafted archive can read or write files outside that directory because hardlink and symlink entries are created without checking where targets point, path containment used a string prefix comparison, and file modes failed to remove setuid, setgid, or sticky bits. This issue is fixed in @xhmikosr/decompress versions 10.2.1 and 11.1.3.

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:
  • https://github.com/XhmikosR/decompress/releases/tag/v10.2.1
  • https://github.com/XhmikosR/decompress/releases/tag/v11.1.3
  • https://github.com/XhmikosR/decompress/commit/aca5aac
  • https://github.com/XhmikosR/decompress/commit/281cefa
  • https://github.com/XhmikosR/decompress/commit/60b5299

TuxCare rebuilt decompress to address 2 CVEs. Fixed in 4.2.1-tuxcare.2.

Root has patched CVE-2026-53486 in the @xhmikosr/decompress package for Root:npm. Multiple fixed versions available.