CVE-2021-21300 Detail

Current 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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  7.5 HIGH
Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  8.0 HIGH
Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://seclists.org/fulldisclosure/2021/Apr/60 Mailing List  Third Party Advisory 
http://www.openwall.com/lists/oss-security/2021/03/09/3 Exploit  Mailing List  Third Party Advisory 
https://git-scm.com/docs/git-config#Documentation/git-config.txt-coresymlinks Vendor Advisory 
https://git-scm.com/docs/gitattributes#_filter Vendor Advisory 
https://github.com/git/git/commit/684dd4c2b414bcf648505e74498a608f28de4592 Patch  Third Party Advisory 
https://github.com/git/git/security/advisories/GHSA-8prw-h3cq-mghm Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BBPNGLQSYJHLZZ37BO42YY6S5OTIF4L4/ Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LCLJJLKKMS5WRFO6C475AOUZTWQLIARX/ Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LMXX2POK5X576BSDWSXGU7EIK6I72ERU/ Mailing List  Third Party Advisory 
https://lore.kernel.org/git/xmqqim6019yd.fsf@gitster.c.googlers.com/ Release Notes  Third Party Advisory 
https://security.gentoo.org/glsa/202104-01 Third Party Advisory 
https://support.apple.com/kb/HT212320 Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-59 Improper Link Resolution Before File Access ('Link Following') cwe source acceptance level NIST   Provider acceptance level GitHub, Inc.  

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Change History

11 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-21300
NVD Published Date:
03/09/2021
NVD Last Modified:
05/05/2021
Source:
GitHub, Inc.