CVE-2021-21300

Summary

Git is an open-source distributed revision control system. In affected versions of Git a specially crafted repository that contains symbolic links as well as files using a clean/smudge filter such as Git LFS, may cause just-checked out script to be executed while cloning onto a case-insensitive file system such as NTFS, HFS+ or APFS (i.e. the default file systems on Windows and macOS). Note that clean/smudge filters have to be configured for that. Git for Windows configures Git LFS by default, and is therefore vulnerable. The problem has been patched in the versions published on Tuesday, March 9th, 2021. As a workaound, if symbolic link support is disabled in Git (e.g. via git config --global core.symlinks false), the described attack won't work. Likewise, if no clean/smudge filters such as Git LFS are configured globally (i.e. before cloning), the attack is foiled. As always, it is best to avoid cloning repositories from untrusted sources. The earliest impacted version is 2.14.2. The fix versions are: 2.30.1, 2.29.3, 2.28.1, 2.27.1, 2.26.3, 2.25.5, 2.24.4, 2.23.4, 2.22.5, 2.21.4, 2.20.5, 2.19.6, 2.18.5, 2.17.62.17.6.

Affected Software

VendorProductVersion RangeStatus
gitgit>= 2.14.2, < 2.17.62.17.6affected
gitgit>= 2.18.0, < 2.18.5affected
gitgit>= 2.19.0, < 2.19.6affected
gitgit>= 2.20.0, < 2.20.5affected
gitgit>= 2.21.0, < 2.21.4affected
gitgit>= 2.22.0, < 2.22.5affected
gitgit>= 2.23.0, < 2.23.4affected
gitgit>= 2.24.0, < 2.24.4affected
gitgit>= 2.25.0, < 2.25.5affected
gitgit>= 2.26.0, < 2.26.3affected
gitgit>= 2.27.0, < 2.27.1affected
gitgit>= 2.28.0, < 2.28.1affected
gitgit>= 2.29.0, < 2.29.3affected
gitgit>= 2.30.0, < 2.30.1affected

Weaknesses

  • CWE-59: CWE-59 Improper Link Resolution Before File Access ('Link Following')

ADP Enrichment

CVE Program Container

Additional References

References