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NVD / CVE Program· CNA GitHub_M

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

Noroxi assessment

Priority: This week (action score 60/100)

  • A ready-made attack module is public (Metasploit); exploiting it takes no special expertise.
  • A ready-made attack tool exists and the flaw can be exploited over the network without an account, so priority is at least “This week”.
  • Probability of exploitation in the next 30 days: 88.5% (FIRST EPSS); higher than 99.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
  • Fixed version: git (Alpine:v3.10) 2.22.5-r0; git (Alpine:v3.11) 2.24.4-r0; git (Alpine:v3.12) 2.26.3-r0.

Don’t wait for the next maintenance window. Upgrade to git (Alpine:v3.10) 2.22.5-r0; git (Alpine:v3.11) 2.24.4-r0; git (Alpine:v3.12) 2.26.3-r0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—Weaponized Fix available
Published
Mar 9, 2021
Updated
Jun 16, 2026
EPSS
88.5% · 99th percentile

Report tools

JSON

Action score

60

This week

Don’t wait for the next maintenance window.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
27 / 30 · 88.5%
Ready-made attack tool
3 / 60 · floor: at least 60

CNA vs NVD score

NVD
7.5
CNA · GitHub_M
8.0
0.5 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-21300

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
git-scmgit
fedoraprojectfedora
applexcode
applemacos
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apple xcodebefore 12.5
  • debian debian linux10.0
  • fedoraproject fedora32
  • fedoraproject fedora33
  • fedoraproject fedora34
  • git-scm git2.21.0 and later · before 2.21.4
  • git-scm git2.22.0 and later · before 2.22.5
  • git-scm git2.23.0 and later · before 2.23.4
  • git-scm git2.24.0 and later · before 2.24.4
  • git-scm git2.25.0 and later · before 2.25.5
  • git-scm gitup to 2.14.2 inclusive
  • git-scm git2.29.0 and later · before 2.29.3
  • git-scm git2.30.0 and later · before 2.30.2
  • git-scm git2.26.0 and later · before 2.26.3
  • git-scm git2.17.0 and later · before 2.17.6
  • git-scm git2.18.0 and later · before 2.18.5
  • git-scm git2.19.0 and later · before 2.19.6
  • git-scm git2.20.0 and later · before 2.20.5
  • git-scm git2.27.0
  • git-scm git2.28.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • git git

    • >= 2.14.2, < 2.17.62.17.6, >= 2.18.0, < 2.18.5, >= 2.19.0, < 2.19.6, >= 2.20.0, < 2.20.5, >= 2.21.0, < 2.21.4, >= 2.22.0, < 2.22.5, >= 2.23.0, < 2.23.4, >= 2.24.0, < 2.24.4, >= 2.25.0, < 2.25.5, >= 2.26.0, < 2.26.3, >= 2.27.0, < 2.27.1, >= 2.28.0, < 2.28.1 … (+2)affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.10gitfrom 2.17.0 · before 2.22.5-r02.22.5-r0
Alpine:v3.11gitfrom 2.17.0 · before 2.24.4-r02.24.4-r0
Alpine:v3.12gitfrom 2.17.0 · before 2.26.3-r02.26.3-r0
Alpine:v3.13gitfrom 2.17.0 · before 2.30.2-r02.30.2-r0
Debian:10gitbefore 1:2.20.1-2+deb10u41:2.20.1-2+deb10u4
Debian:12gitbefore 1:2.30.2-11:2.30.2-1
openSUSE:Leap 15.2gitbefore 2.26.2-lp152.2.6.12.26.2-lp152.2.6.1
openSUSE:Leap 15.3gitbefore 2.31.1-10.3.12.31.1-10.3.1
openSUSE:Tumbleweedgit-annexbefore 8.20210903-1.28.20210903-1.2
SUSE:HPE Helion OpenStack 8gitbefore 2.26.2-27.43.12.26.2-27.43.1
SUSE:Linux Enterprise Module for Basesystem 15 SP2gitbefore 2.26.2-3.31.12.26.2-3.31.1
SUSE:Linux Enterprise Module for Basesystem 15 SP3gitbefore 2.31.1-10.3.12.31.1-10.3.1

Same product

git-scm: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-17456Git before 2.14.5, 2.15.x before 2.15.3, 2.16.x before 2.16.5, 2.17.x before 2.17.2, 2.18.x before 2.18.1, and 2.19.x before 2.19.1 allows r
    68This week
  • CVE-2025-48384Git allows arbitrary code execution through broken config quotingKEV
    63This week
  • CVE-2017-1000117A malicious third-party can give a crafted "ssh://..." URL to an unsuspecting victim, and an attempt to visit the URL can result in any prog
    60This week

Published before and after this one in the same product

  • ← EarlierCVE-2019-1353Jan 24, 2020 · An issue was found in Git before v2.24.1, v2.23.1, v2.22.2, v2.21.1, v2.20.2, v2.19.3, v2.18.2, v2.17.3, v2.16.6, v2.15.4, and v2.14.6.
    40Plan
  • ← EarlierCVE-2020-11008Apr 21, 2020 · Malicious URLs can still cause Git to send a stored credential to the wrong server
    31Monitor
  • Later →CVE-2021-40330Aug 31, 2021 · git_connect_git in connect.c in Git before 2.30.1 allows a repository path to contain a newline character, which may result in unexpected cr
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:git2.22.5-r0 · Alpine:v3.10Package registry (OSV)
debian:git1:2.30.2-1 · Debian:12Package registry (OSV)
opensuse:git2.26.2-lp152.2.6.1 · openSUSE:Leap 15.2Package registry (OSV)
opensuse:git-annex8.20210903-1.2 · openSUSE:TumbleweedPackage registry (OSV)
suse:git2.26.2-27.43.1 · SUSE:HPE Helion OpenStack 8Package registry (OSV)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Proof-of-concept repository on GitHub ×14

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Metasploit moduleexploit/multi/http/git_lfs_clone_command_execGit LFS Clone Command Execexploit2021-04-26
Proof-of-concept repository on GitHubstars:02021-03-10
Proof-of-concept repository on GitHubstars:02021-03-10
Proof-of-concept repository on GitHubstars:02021-03-10
Proof-of-concept repository on GitHubstars:12021-03-11
Proof-of-concept repository on GitHubstars:02021-03-11
Proof-of-concept repository on GitHubstars:02021-03-11
Proof-of-concept repository on GitHubstars:02021-03-15
Proof-of-concept repository on GitHubstars:02021-04-06
Proof-of-concept repository on GitHubstars:02021-04-07
Proof-of-concept repository on GitHubstars:02022-08-13
Proof-of-concept repository on GitHubstars:02023-05-04

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoCsame day
  3. Metasploit+47 d
  4. TodayNov 6, 2026+2068 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

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

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (11 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records