bzip2 could overwrite files during file decompression

bzip2-decompression-file-overwrite (9126) The risk level is classified as MediumMedium Risk


bzip2 fails to properly check for the prior existence of files during decompression, which could cause arbitrary files to be overwritten.


File Manipulation


Upgrade to the latest version of bzip2 (1.0.2 or later), available from the bzip2 Web page. See References.

For FreeBSD:
Apply the patch for this vulnerability, as listed in FreeBSD Security Advisory FreeBSD-SA-02:25. See References.

For CalderaOpenLinux Server and Workstation 3.1 and 3.1.1:
Upgrade to the latest bzip2 package (1.0.0-7MR or later) as listed in SCO Security Advisory CSSA-2002-039.0. See References.

For other distributions:
Contact your vendor for upgrade or patch information.


  • bzip2 Web site: The bzip2 and libbzip2 official home page.
  • FreeBSD Security Advisory FreeBSD-SA-02:25: bzip2 contains multiple security vulnerabilities.
  • SCO Security Advisory CSSA-2002-039.0: Linux: bzip2 file creation and symbolic link vulnerabilities.
  • BID-4774: bzip2 Decompression File Overwrite Vulnerability
  • CVE-2002-0759: bzip2 before 1.0.2 in FreeBSD 4.5 and earlier, OpenLinux 3.1 and 3.1.1, and possibly other operating systems, does not use the O_EXCL flag to create files during decompression and does not warn the user if an existing file would be overwritten, which could allow attackers to overwrite files via a bzip2 archive.
  • OSVDB ID: 5117: bzip2 Decompress Overwrite Arbitrary Files

Platforms Affected:

  • FreeBSD FreeBSD 4.4
  • FreeBSD FreeBSD 4.5
  • Julian Seward bzip2 1.0.1 and prior
  • SCO Caldera OpenLinux Server 3.1
  • SCO Caldera OpenLinux Server 3.1.1
  • SCO Caldera OpenLinux Workstation 3.1
  • SCO Caldera OpenLinux Workstation 3.1.1


May 20, 2002

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