libgit2 v0.27.0-v1.9.0 Shell Command Injection via ssh_libssh2 Backend

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-5917
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-11 22:17:37 UTC
Updated2026-08-12 13:17:23 UTC
Descriptionlibgit2 versions v0.27.0 through v1.9.0 built with the libssh2 SSH backend (USE_SSH=libssh2) contain a shell command injection vulnerability that allows remote attackers to execute arbitrary commands on an SSH server by supplying a repository path containing unescaped shell metacharacters such as single quotes, semicolons, or pipes. The gen_proto() function in ssh_libssh2.c inserts the repository path directly into a shell command string without escaping special characters before passing it to libssh2_channel_exec(), enabling an attacker to craft a malicious submodule URL in a .gitmodules file that, when processed during a recursive clone, causes the remote server's shell to interpret injected commands under the victim's SSH user account.

Risk And Classification

Primary CVSS: v4.0 9.4 CRITICAL from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.008590000 probability, percentile 0.552400000 (date 2026-08-12)

Problem Types: CWE-78 | CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary9.4CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/C...
4.0CNACVSS9.4CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
3.1[email protected]Secondary9.6CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
3.1CNACVSS9.6CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
High
Sub Integrity
High
Sub Availability
High

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Libgit2 Libgit2 affected 0.27.0 1.9.0 custom Not specified

References

ReferenceSourceLinkTags
github.com/libgit2/libgit2 [email protected] github.com
www.vulncheck.com/advisories/libgit2-shell-command-injection-via-ssh-libssh2-ba... [email protected] www.vulncheck.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Kazuma Matsumoto, a security researcher at GMO Cybersecurity by IERAE, Inc. (en)

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