CVE & CISA-KEV Catalog

CVE-2021-21300

HIGHEPSS 100th pctl
8.0
CVSS v3
NVD

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.

How to fix

Remediation Available
gitDebian
Fixed in:1:2.30.2-1CVE-2021-21300
Fixed in:1:2.30.2-1CVE-2021-21300
Fixed in:1:2.30.2-1CVE-2021-21300
Fixed in:1:2.30.2-1CVE-2021-21300
gitUbuntu
Fixed in:1:2.7.4-0ubuntu1.10USN-4761-1
Fixed in:1:2.17.1-1ubuntu0.8USN-4761-1
Fixed in:1:2.25.1-1ubuntu3.1USN-4761-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionRequired
ScopeChanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityNone

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

Exploit Intelligence

88.64%probability of exploitation in 30 days
100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

References

Related Vulnerabilities

Other CWE-59 (Link Following) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2022-30333High7.599%KEV + RansomFix
CVE-2021-32610High7.173%-Fix
CVE-2020-36193High7.571%KEVFix
CVE-2023-40028Medium4.958%-Fix
CVE-2023-36874High7.843%KEVFix
CVE-2020-0787High7.843%KEV + Ransom-

Common questions

How do I fix CVE-2021-21300?

Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2021-21300 being actively exploited?

Not that we know of. CVE-2021-21300 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 88.6% is the estimated probability that it will be exploited in the next 30 days. That is higher than 100% of all scored CVEs.

How severe is CVE-2021-21300?

CVE-2021-21300 has a CVSS v3 base score of 8.0, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-21300 affect?

Published advisories record a fix for git (Debian), git (Ubuntu). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.