Cross-Site Scripting (XSS) in librenms/librenms (CVE-2026-45694)
Summary
Cross-site scripting in librenms/librenms (CVE-2026-45694). Risk of unauthorized operations or information disclosure. Exploitable via document.title. Mitigation: upgrade to 26.5.0 or later.
Original description
The description as published by the source.
Summary
LegacyController.php:75 writes the page title into a document.title JS assignment using string interpolation. apps/proxmox.inc.php pushes $vars['instance'] and $vars['vmid'] (GET params, only strip_tags() applied) directly into $pagetitle. A single quote terminates the JS string, executing arbitrary script.
Details
// LegacyController.php:75
$html .= "\ndocument.title = '$title';\n";
// proxmox.inc.php:38,42
$pagetitle[] = $instance; // GET ?instance=
$pagetitle[] = $vars['vmid']; // GET ?vmid=
PoC
http://target/apps?app=proxmox&instance=%27%3Balert%28document.cookie%29%3B//
Confirmed in response:
document.title = 'Apps - Proxmox - ';alert(document.cookie);// - LibreNMS';
Fix
// LegacyController.php:75
$html .= "\ndocument.title = " . json_encode($title) . ";\n";
Also wrap $instance and $vars['vmid'] in htmlspecialchars() in proxmox.inc.php.
Prerequisite
Any authenticated session. Victim must follow a crafted link.
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-2026-45694 has been found in librenms/librenms.
Attackers can target a specific entry point like document.title over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.4/10.
What to do: upgrade librenms/librenms to 26.5.0 or later.
If unsure, ask your IT team or search "librenms/librenms CVE-2026-45694" on the vendor's site.
CVE-2026-45694 (librenms/librenms) — CWE-79 / CVSS v3 5.4
Attack vector: remote (network-reachable)
Attack surface: document.title
Patched: 26.5.0 — 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.
Cross-site scripting (XSS) (CWE-79) exists in librenms/librenms. Attackers reach the vulnerable code path via document.title.
Check the vendor advisory for the affected versions of librenms/librenms. Attack surface: document.title.
Severity: Medium (CVSS 5.4/10). Risk of unauthorized operations or information disclosure.
Update to 26.5.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'librenms/librenms' . 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
-
1Identify exposure identify
grep -r 'librenms/librenms' . | 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
librenms/librenmsを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade librenms/librenms to 26.5.0ステージング環境で 26.5.0 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。
-
3Post-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
References
- package github.com
- web github.com
- web github.com
- web github.com
- web security-advisories@github.com