CVE-2021-21300
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…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 88.5%, higher than 100% of all known CVEs. Patch or mitigate before the next change window.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 88.53% probability · 100th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-59
- Affected
- git-scm/git · fedoraproject/fedora · apple/xcode · debian/debian linux
- Source
- security-advisories@github.com
References
- http://packetstormsecurity.com/files/163978/Git-LFS-Clone-Command-Execution.htmlExploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2021/Apr/60Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/03/09/3Exploit, Mailing List, Third Party Advisory
- https://git-scm.com/docs/git-config#Documentation/git-config.txt-coresymlinksVendor Advisory
- https://git-scm.com/docs/gitattributes#_filterVendor Advisory
- https://github.com/git/git/commit/684dd4c2b414bcf648505e74498a608f28de4592Patch, Third Party Advisory
- https://github.com/git/git/security/advisories/GHSA-8prw-h3cq-mghmThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/10/msg00014.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBPNGLQSYJHLZZ37BO42YY6S5OTIF4L4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCLJJLKKMS5WRFO6C475AOUZTWQLIARX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LMXX2POK5X576BSDWSXGU7EIK6I72ERU/
- https://lore.kernel.org/git/xmqqim6019yd.fsf%40gitster.c.googlers.com/
- https://security.gentoo.org/glsa/202104-01Third Party Advisory
- https://support.apple.com/kb/HT212320Third Party Advisory
- http://packetstormsecurity.com/files/163978/Git-LFS-Clone-Command-Execution.htmlExploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2021/Apr/60Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/03/09/3Exploit, Mailing List, Third Party Advisory
- https://git-scm.com/docs/git-config#Documentation/git-config.txt-coresymlinksVendor Advisory
- https://git-scm.com/docs/gitattributes#_filterVendor Advisory
- https://github.com/git/git/commit/684dd4c2b414bcf648505e74498a608f28de4592Patch, Third Party Advisory
- https://github.com/git/git/security/advisories/GHSA-8prw-h3cq-mghmThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/10/msg00014.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBPNGLQSYJHLZZ37BO42YY6S5OTIF4L4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCLJJLKKMS5WRFO6C475AOUZTWQLIARX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LMXX2POK5X576BSDWSXGU7EIK6I72ERU/
- https://lore.kernel.org/git/xmqqim6019yd.fsf%40gitster.c.googlers.com/
- https://security.gentoo.org/glsa/202104-01Third Party Advisory
- https://support.apple.com/kb/HT212320Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.