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CVE-2026-40243
medium
CVSS 4.8
Authentication Bypass in github.com/lxc/incus/v6/cmd/incusd (CVE-2026-40243)
Summary
authentication bypass in github.com/lxc/incus/v6/cmd/incusd (CVE-2026-40243). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to `7.0.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-40243** has been found in github.com/lxc/incus/v6/cmd/incusd.
Risk of unauthorized operations or information disclosure. CVSS score: 4.8/10.
What to do: upgrade github.com/lxc/incus/v6/cmd/incusd to **7.0.0** or later.
If unsure, ask your IT team or search "github.com/lxc/incus/v6/cmd/incusd CVE-2026-40243" on the vendor's site.
CVE-2026-40243 (github.com/lxc/incus/v6/cmd/incusd) — CWE-287 / CVSS v3 4.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: `7.0.0` — 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
**authentication bypass** (CWE-287) exists in github.com/lxc/incus/v6/cmd/incusd.
📍 Affected scope
github.com/lxc/incus/v6/cmd/incusd — .
🔥 Severity
Severity: Medium (CVSS 4.8/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **7.0.0**.
🛡️ 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 'github.com/lxc/incus/v6/cmd/incusd' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'github.com/lxc/incus/v6/cmd/incusd' . | 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 `github.com/lxc/incus/v6/cmd/incusd` を grep し、稼働しているサービス・バージョンを把握する。
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6Apply patch patch
Upgrade github.com/lxc/incus/v6/cmd/incusd to 7.0.0ステージング環境で 7.0.0 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と、Step 3 で見つけた異常検知の続報チェックを含めること。
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7Post-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 Step 3 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
go
github.com/lxc/incus/v6/cmd/incusd
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.0.0"}]}]
References
- web https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icnb.go
- web https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icsb.go
- web https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_nb.go
- web https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_sb.go
- web https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3
- web https://nvd.nist.gov/vuln/detail/CVE-2026-40243
- web https://github.com/advisories/GHSA-c839-4qxr-j4x3