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CVE-2026-40034 gitoxide CVE debrief

CVE-2026-40034 is a high-severity command injection vulnerability in gix-submodule versions prior to 0.82.0. The flaw stems from improper validation of the `update` field in `.gitmodules` files, allowing attackers to bypass the `CommandForbiddenInModulesConfiguration` security guard. When a submodule has been initialized with only partial configuration in `.git/config`, an attacker can inject arbitrary shell commands via the `update` field that execute when `Submodule::update()` is called, enabling remote code execution. The vulnerability was published on 2026-05-26 and affects the gitoxide project's gix-submodule crate. Two commits address this issue, and a GitHub Security Advisory has been issued. Organizations using gix-submodule should upgrade to version 0.82.0 or later and audit submodule configurations for unauthorized `update` field modifications.

Vendor
gitoxide
Product
Unknown
CVSS
HIGH 7.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-26
Original CVE updated
2026-10-08
Advisory published
2026-05-26
Advisory updated
2026-10-08

Who should care

Organizations using gitoxide's gix-submodule crate in Rust applications, particularly those implementing Git automation or CI/CD pipelines with submodule operations. Software supply chain security teams should prioritize this due to potential for remote code execution in automated environments.

Technical summary

The gix-submodule crate in gitoxide fails to properly validate the `update` field in `.gitmodules` when a submodule has been initialized with partial configuration. The `CommandForbiddenInModulesConfiguration` guard is bypassed in this scenario, allowing shell command injection. When `Submodule::update()` is invoked, the attacker-controlled `update` field content executes as a shell command. This represents a state-dependent vulnerability where the security boundary depends on the initialization state of the submodule configuration.

Defensive priority

HIGH

Recommended defensive actions

  • Upgrade gix-submodule to version 0.82.0 or later
  • Audit existing .gitmodules files for unauthorized update field modifications
  • Review submodule initialization workflows for partial configuration scenarios
  • Implement code review processes for submodule configuration changes
  • Monitor for suspicious submodule update operations in CI/CD pipelines

Evidence notes

The vulnerability description is sourced from the official CVE record and NVD entry. The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N) indicates local attack vector with high impact on confidentiality, integrity, and availability. CWE-77 (Command Injection) is identified as the weakness type. Two commits are referenced as remediation: 6a2e6a436f76c8bbf2487f9967413a51356667a0 and dd5c18d9e526e8de462fa40aa047acd097cfa7dc.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-40034 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-40034

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-40034 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-40034

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.