CVE-2021-21300Public exploitNetwork attack vector

Code execution via stale checkout path cache

Published Mar 9, 2021 · Updated Aug 3, 2024

Remote code execution in Git allows remote attackers to execute code by inducing a user to clone a specially crafted repository. During delayed checkout, a case or Unicode path collision can leave the lstat directory cache stale, so checkout follows a replacement symlink and writes an attacker-controlled file outside the repository. Exploitation requires user interaction, a case-insensitive filesystem with symbolic-link support, and a globally configured delay-capable clean/smudge filter.

CVSS severity8.0
High
EPSS probability88.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Git allows remote attackers to execute code by inducing a user to clone a specially crafted repository. During delayed checkout, a case or Unicode path collision can leave the lstat directory cache stale, so checkout follows a replacement symlink and writes an attacker-controlled file outside the repository. Exploitation requires user interaction, a case-insensitive filesystem with symbolic-link support, and a globally configured delay-capable clean/smudge filter.

The record

CVE
CVE-2021-21300
Published
Mar 9, 2021
Updated
Aug 3, 2024
Vendor
Git
Product
Git
Classifications
T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.14.2, < 2.17.62.17.6
  2. Affected versionversion=>= 2.18.0, < 2.18.5
  3. Affected versionversion=>= 2.19.0, < 2.19.6
  4. Affected versionversion=>= 2.20.0, < 2.20.5
  5. Affected versionversion=>= 2.21.0, < 2.21.4
  6. Affected versionversion=>= 2.22.0, < 2.22.5
  7. Affected versionversion=>= 2.23.0, < 2.23.4
  8. Affected versionversion=>= 2.24.0, < 2.24.4
  9. Affected versionversion=>= 2.25.0, < 2.25.5
  10. Affected versionversion=>= 2.26.0, < 2.26.3
  11. Affected versionversion=>= 2.27.0, < 2.27.1
  12. Affected versionversion=>= 2.28.0, < 2.28.1
  13. Affected versionversion=>= 2.29.0, < 2.29.3
  14. Affected versionversion=>= 2.30.0, < 2.30.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Git · Gitversion=>= 2.14.2, < 2.17.62.17.6; version=>= 2.18.0, < 2.18.5; version=>= 2.19.0, < 2.19.6; version=>= 2.20.0, < 2.20.5; version=>= 2.21.0, < 2.21.4; version=>= 2.22.0, < 2.22.5; version=>= 2.23.0, < 2.23.4; version=>= 2.24.0, < 2.24.4; version=>= 2.25.0, < 2.25.5; version=>= 2.26.0, < 2.26.3; version=>= 2.27.0, < 2.27.1; version=>= 2.28.0, < 2.28.1; version=>= 2.29.0, < 2.29.3; version=>= 2.30.0, < 2.30.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
8.0GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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