CVE-2021-21300 malicious repositories can execute remote code while cloning

2021-03-0900:00:00

CWE-59

GitHub_M

www.cve.org

8 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

7.9 High

AI Score

Confidence

High

0.885 High

EPSS

Percentile

98.7%

JSON

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.

CNA Affected

[
  {
    "vendor": "git",
    "product": "git",
    "versions": [
      {
        "version": ">= 2.14.2, < 2.17.62.17.6",
        "status": "affected"
      },
      {
        "version": ">= 2.18.0, < 2.18.5",
        "status": "affected"
      },
      {
        "version": ">= 2.19.0, < 2.19.6",
        "status": "affected"
      },
      {
        "version": ">= 2.20.0, < 2.20.5",
        "status": "affected"
      },
      {
        "version": ">= 2.21.0, < 2.21.4",
        "status": "affected"
      },
      {
        "version": ">= 2.22.0, < 2.22.5",
        "status": "affected"
      },
      {
        "version": ">= 2.23.0, < 2.23.4",
        "status": "affected"
      },
      {
        "version": ">= 2.24.0, < 2.24.4",
        "status": "affected"
      },
      {
        "version": ">= 2.25.0, < 2.25.5",
        "status": "affected"
      },
      {
        "version": ">= 2.26.0, < 2.26.3",
        "status": "affected"
      },
      {
        "version": ">= 2.27.0, < 2.27.1",
        "status": "affected"
      },
      {
        "version": ">= 2.28.0, < 2.28.1",
        "status": "affected"
      },
      {
        "version": ">= 2.29.0, < 2.29.3",
        "status": "affected"
      },
      {
        "version": ">= 2.30.0, < 2.30.1",
        "status": "affected"
      }
    ]
  }
]