CVE-2021-21300
published 2021-03-09CVE-2021-21300: 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…
PriorityP275high7.5CVSS 3.1
AVNACHPRNUIRSUCHIHAH
EXPLOIT
EPSS
88.64%
99.8th percentile
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.
Affected
44 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| apple | xcode | < 12.5 | 12.5 |
| debian | debian_linux | — | — |
| debian | git | < git 1:2.30.2-1 (bookworm) | git 1:2.30.2-1 (bookworm) |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| fedoraproject | fedora | — | — |
| git-scm | git | <= 2.14.2 | — |
| git-scm | git | — | — |
| git-scm | git | — | — |
| git-scm | git | >= 2.17.0 < 2.17.6 | 2.17.6 |
| git-scm | git | >= 2.18.0 < 2.18.5 | 2.18.5 |
| git-scm | git | >= 2.19.0 < 2.19.6 | 2.19.6 |
| git-scm | git | >= 2.20.0 < 2.20.5 | 2.20.5 |
| git-scm | git | >= 2.21.0 < 2.21.4 | 2.21.4 |
| git-scm | git | >= 2.22.0 < 2.22.5 | 2.22.5 |
| git-scm | git | >= 2.23.0 < 2.23.4 | 2.23.4 |
| git-scm | git | >= 2.24.0 < 2.24.4 | 2.24.4 |
| git-scm | git | >= 2.25.0 < 2.25.5 | 2.25.5 |
| git-scm | git | >= 2.26.0 < 2.26.3 | 2.26.3 |
| git-scm | git | >= 2.29.0 < 2.29.3 | 2.29.3 |
| git-scm | git | >= 2.30.0 < 2.30.2 | 2.30.2 |
| git | git | — | — |
| git | git | — | — |
| git | git | — | — |
| git | git | — | — |
Detection & IOCsextracted from sources · hover to see the quote
- →Monitor for unexpected creation or modification of files inside the `.git/hooks/` directory during a `git clone` operation, especially `post-checkout`, which is the default hook written by the Metasploit exploit module. ↗
- →Detect exploitation attempts by monitoring for symbolic links being checked out alongside files processed by clean/smudge filters (e.g., Git LFS) during clone operations on case-insensitive file systems (NTFS, HFS+, APFS). ↗
- →Alert on `git clone` processes that spawn unexpected child processes, particularly on Windows (NTFS) or macOS (HFS+/APFS) systems, as the exploit causes a checked-out script to execute automatically during clone. ↗
- →Flag Git clients with `core.symlinks` set to true (default) AND Git LFS configured globally, as both conditions together are required for exploitation. ↗
- →Git for Windows installations should be treated as vulnerable by default since Git LFS is configured out-of-the-box, making all default Git for Windows installs susceptible without additional hardening. ↗
- ·The exploit requires BOTH symbolic link support enabled (core.symlinks=true, which is the default) AND a clean/smudge filter such as Git LFS configured globally before cloning. Disabling either condition independently prevents exploitation. ↗
- ·The vulnerability is specific to case-insensitive file systems (NTFS, HFS+, APFS). Typical Linux case-sensitive file systems are not affected, though exploitation is possible on Linux under certain circumstances (e.g., ext4 per-directory case-insensitive directories). ↗
- ·The earliest impacted Git version is 2.14.2; versions 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, and 2.17.6 contain the fix. ↗
- ·Red Hat CodeReady Studio 12 is not affected because it uses jgit (a Java Git implementation), not the native git binary. ↗
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
nvdv2.05.1MEDIUMAV:N/AC:H/Au:N/C:P/I:P/A:P
osv7.5HIGH
vendor_msrc8.8HIGH
vendor_debian8.0HIGH
vendor_redhat8.0HIGH
CVEs like this are exactly what “Exploited This Week” covers.
Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.
Microsoft
Git for Visual Studio Remote Code Execution Vulnerability
vendor_msrc·2021-03-09·CVSS 8.8
CVE-2021-21300 [HIGH] Git for Visual Studio Remote Code Execution Vulnerability
Git for Visual Studio Remote Code Execution Vulnerability
Visual Studio: Visual Studio
GitHub (maintainer security advisories): GitHub (maintainer security advisories)
Impact: Remote Code Execution
Exploit Status: Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely;Older Software Release:Exploitation Less Likely;DOS:N/A
Remediation: Release Notes
Reference: http://aka.ms/vs/15/release/latest
Reference: http://aka.ms/vs/16/release/latest
Reference: https://my.visualstudio.com/Downloads?q=Visual Studio 2019 version 16.7
Red Hat
git: remote code execution during clone operation on case-insensitive filesystems
vendor_redhat·2021-03-09·CVSS 8.0
CVE-2021-21300 [HIGH] CWE-59 git: remote code execution during clone operation on case-insensitive filesystems
git: remote code execution during clone operation on case-insensitive filesystems
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
Ubuntu
Git vulnerability
vendor_ubuntu·2021-03-09
CVE-2021-21300 Git vulnerability
Title: Git vulnerability
Summary: Git could be made to run programs if it received specially crafted network
traffic.
Matheus Tavares discovered that Git incorrectly handled delay-capable
clean/smudge filters when being used on case-insensitive filesystems. A
remote attacker could possibly use this issue to execute arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Debian
CVE-2021-21300: git - Git is an open-source distributed revision control system. In affected versions ...
vendor_debian·2021·CVSS 8.0
CVE-2021-21300 [HIGH] CVE-2021-21300: git - Git is an open-source distributed revision control system. In affected versions ...
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
OSV
CVE-2021-21300: Git is an open-source distributed revision control system
osv·2021-03-09·CVSS 7.5
CVE-2021-21300 [HIGH] CVE-2021-21300: Git is an open-source distributed revision control system
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
No detection rules found.
arXiv
ZeroDayBench: Evaluating LLM Agents on Unseen Zero-Day Vulnerabilities for Cyberdefense
arxiv_fulltext·2026-03-02
ZeroDayBench: Evaluating LLM Agents on Unseen Zero-Day Vulnerabilities for Cyberdefense
## Abstract
Large language models (LLMs) are increasingly being deployed as software engineering agents that autonomously contribute to repositories. A major benefit these agents present is their ability to find and patch security vulnerabilities in the codebases they oversee. To estimate the capability of agents in this domain, we introduce ZeroDayBench, a benchmark where LLM agents find and patch 22 novel critical vulnerabilities in open-source codebases. We focus our efforts on three popular frontier agentic LLMs: GPT-5.2, Claude Sonnet 4.5, and Grok 4.1. We find that frontier LLMs are not yet capable of autonomously solving our tasks and observe some behavioral patterns that suggest how these models can be improved in the domain of proactive cyberdefense.
## Introduction
Large langu
arXiv
Unsafe at Any Copy: Name Collisions from Mixing Case Sensitivities
arxiv_fulltext·2022-11-30·CVSS 8.0
[HIGH] Unsafe at Any Copy: Name Collisions from Mixing Case Sensitivities
Unsafe at Any Copy: Name Collisions from Mixing Case Sensitivities
*
Aditya Basu
[email protected]
John Sampson
[email protected]
Zhiyun Qian
[email protected]
Trent Jaeger
[email protected]
The Pennsylvania State University
University of California, Riverside
## Abstract
File name confusion attacks, such as malicious symlinks and file squatting, have long been studied as sources of security vulnerabilities. However, a recently emerged type, i.e., case-sensitivity-induced name collisions, has not been scrutinized.
These collisions are introduced by differences in name resolution under case-sensitive and case-insensitive file systems or directories.
A prominent example is the recent Git vulnerability (CVE-2021-21300) which can lead to code execution on a victim client when it clone
arXiv
Unsafe at Any Copy: Name Collisions from Mixing Case Sensitivities
arxiv_cs_cr·2022-11-30·CVSS 8.0
[HIGH] Unsafe at Any Copy: Name Collisions from Mixing Case Sensitivities
Unsafe at Any Copy: Name Collisions from Mixing Case Sensitivities
File name confusion attacks, such as malicious symbolic links and file squatting, have long been studied as sources of security vulnerabilities. However, a recently emerged type, i.e., case-sensitivity-induced name collisions, has not been scrutinized. These collisions are introduced by differences in name resolution under case-sensitive and case-insensitive file systems or directories. A prominent example is the recent Git vulnerability (CVE-2021-21300) which can lead to code execution on a victim client when it clones a maliciously crafted repository onto a case-insensitive file system. With trends including ext4 adding support for per-directory case-insensitivity and the broad deployment of the Windows Subsystem for Lin
Talos
Microsoft Patch Tuesday for March 2021 — Snort rules and prominent vulnerabilities
blogs_talos·2021-03-09·CVSS 8.8
[HIGH] Microsoft Patch Tuesday for March 2021 — Snort rules and prominent vulnerabilities
By Jon Munshaw, with contributions from Nick Biasini.
Microsoft released its monthly security update Tuesday, disclosing 89 vulnerabilities across its suite of products, the most in any month so far this year.
There are 14 critical vulnerabilities as part of this release and one considered of “low” severity. The remainder are all “important.” Three of the critical vulnerabilities are the ones Microsoft disclosed last week in Exchange Server that the company said state-sponsored actors exploited in the wild to steal emails. Microsoft also announced Monday they were releasing patches for older versions of Exchange Server.
All organizations using the affected software should prevent external access to port 443 on Exchange Servers, or set up a VPN to provide external access to port 443. Thi
Talos
Microsoft Patch Tuesday for March 2021 — Snort rules and prominent vulnerabilities
blogs_talos·2021-03-09·CVSS 8.8
[HIGH] Microsoft Patch Tuesday for March 2021 — Snort rules and prominent vulnerabilities
## Microsoft Patch Tuesday for March 2021 — Snort rules and prominent vulnerabilities
By Jon Munshaw, with contributions from Nick Biasini.
Microsoft released its monthly security update Tuesday, disclosing 89 vulnerabilities across its suite of products, the most in any month so far this year.
There are 14 critical vulnerabilities as part of this release and one considered of “low” severity. The remainder are all “important.” Three of the critical vulnerabilities are the ones Microsoft disclosed last week in Exchange Server that the company said state-sponsored actors exploited in the wild to steal emails . Microsoft also announced Monday they were releasing patches for older versions of Exchange Server .
All organizations using the affected software should prevent external access to
Crowdstrike
March 2021 Patch Tuesday: Updates and Analysis
blogs_crowdstrike·CVSS 7.5
CVE-2026-20929 [HIGH] March 2021 Patch Tuesday: Updates and Analysis
STARDUST CHOLLIMA Likely Compromises Axios npm Package Apr 01, 2026
Falcon for IT Supports Windows Secure Boot Certificate Lifecycle Management Apr 01, 2026
Detecting CVE-2026-20929: Kerberos Authentication Relay via CNAME Abuse Mar 31, 2026
How Charlotte AI AgentWorks Fuels Security's Agentic Ecosystem Mar 25, 2026
STARDUST CHOLLIMA Likely Compromises Axios npm Package Apr 01, 2026
Falcon for IT Supports Windows Secure Boot Certificate Lifecycle Management Apr 01, 2026
Detecting CVE-2026-20929: Kerberos Authentication Relay via CNAME Abuse Mar 31, 2026
How Charlotte AI AgentWorks Fuels Security's Agentic Ecosystem Mar 25, 2026
Video Highlights the 4 Key Steps to Successful Incident Response Dec 02, 2019
Helping Non-Security Stakeholders Understand ATT&CK in 10 Minutes or Less [VI
http://packetstormsecurity.com/files/163978/Git-LFS-Clone-Command-Execution.htmlhttp://seclists.org/fulldisclosure/2021/Apr/60http://www.openwall.com/lists/oss-security/2021/03/09/3https://git-scm.com/docs/git-config#Documentation/git-config.txt-coresymlinkshttps://git-scm.com/docs/gitattributes#_filterhttps://github.com/git/git/commit/684dd4c2b414bcf648505e74498a608f28de4592https://github.com/git/git/security/advisories/GHSA-8prw-h3cq-mghmhttps://lists.debian.org/debian-lts-announce/2022/10/msg00014.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBPNGLQSYJHLZZ37BO42YY6S5OTIF4L4/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCLJJLKKMS5WRFO6C475AOUZTWQLIARX/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LMXX2POK5X576BSDWSXGU7EIK6I72ERU/https://lore.kernel.org/git/xmqqim6019yd.fsf%40gitster.c.googlers.com/https://security.gentoo.org/glsa/202104-01https://support.apple.com/kb/HT212320http://packetstormsecurity.com/files/163978/Git-LFS-Clone-Command-Execution.htmlhttp://seclists.org/fulldisclosure/2021/Apr/60http://www.openwall.com/lists/oss-security/2021/03/09/3https://git-scm.com/docs/git-config#Documentation/git-config.txt-coresymlinkshttps://git-scm.com/docs/gitattributes#_filterhttps://github.com/git/git/commit/684dd4c2b414bcf648505e74498a608f28de4592https://github.com/git/git/security/advisories/GHSA-8prw-h3cq-mghmhttps://lists.debian.org/debian-lts-announce/2022/10/msg00014.htmlhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BBPNGLQSYJHLZZ37BO42YY6S5OTIF4L4/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LCLJJLKKMS5WRFO6C475AOUZTWQLIARX/https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LMXX2POK5X576BSDWSXGU7EIK6I72ERU/https://lore.kernel.org/git/xmqqim6019yd.fsf%40gitster.c.googlers.com/https://security.gentoo.org/glsa/202104-01https://support.apple.com/kb/HT212320
2021-03-09
Published