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CVE-2026-40034 high CVSS 7.8

Command Injection in gix (CVE-2026-40034)

Summary

Command injection in gix (CVE-2026-40034). Successful exploitation can lead to full system takeover. Exploitable via update. Mitigation: upgrade to 0.83.0 or later.

Original description

The description as published by the source.

Summary

gix_submodule::File::update() is the API that gates whether an attacker-supplied .gitmodules file may set update = !. The function is designed to return Err(CommandForbiddenInModulesConfiguration) unless the !command value came from a trusted local source (.git/config). Git CVE CVE-2019-19604 illustrates why this check is necessary.

However, the guard is implemented incorrectly: it checks whether any section with the same submodule name exists from a non-.gitmodules source; it does not verify that the update value came from that section.

Once a submodule has been initialized (any workflow that writes submodule..url to .git/config), and the attacker subsequently adds update = !cmd to .gitmodules, the guard passes while the command value falls through to the attacker-controlled file.

On an identical repository state, git submodule update aborts with fatal: invalid value for 'submodule.sub.update', while gix::Submodule::update() returns Ok(Some(Update::Command("touch /tmp/pwned"))).

The vulnerable code was introduced in https://github.com/GitoxideLabs/gitoxide/commit/6a2e6a436f76c8bbf2487f9967413a51356667a0.

Details

The vulnerable method is gix_submodule::File::update: https://github.com/GitoxideLabs/gitoxide/blob/main/gix-submodule/src/access.rs#L168-L193:

pub fn update(&self,…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-40034 has been found in gix.
Attackers can target a specific entry point like update over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: upgrade gix to 0.83.0 or later.
If unsure, ask your IT team or search "gix CVE-2026-40034" on the vendor's site.

CVE-2026-40034 (gix) — CWE-77 / CVSS v3 7.8
Attack vector: local / unauthenticated
Attack surface: update / git / init / append_submodule_overrides
Patched: 0.83.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-77) exists in gix. Attackers reach the vulnerable code path via update without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of gix. Attack surface: update / git / init / append_submodule_overrides.

🔥 Severity

Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 0.83.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'gix' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'gix' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で gix を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade gix to 0.83.0

    ステージング環境で 0.83.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

rust gix
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.83.0"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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