Cross-Site Scripting (XSS) in getgrav/grav (CVE-2026-42611)
Summary
Cross-site scripting in getgrav/grav (CVE-2026-42611). Confidential information can be exposed externally. Exploitable via POST /grav-log. Mitigation: upgrade to 2.0.0-beta.2 or later.
Original description
The description as published by the source.
Summary
A low-privileged (with the ability to create a page) user can cause XSS with the injection of svg element. The XSS can further be escalated to dump the entire system information available under /admin/config/info whenever a Super Admin visits the page; which can further be chained with the use of admin-nonce to do a complete server compromise (RCE).
Details
Affected endpoint: admin/pages/
Affected code: system/src/Grav/Common/Security.php
public static function detectXss($string, array $options = null): ?string
{
// Skip any null or non string values
if (null === $string || !is_string($string) || empty($string)) {
return null;
}
if (null === $options) {
$options = static::getXssDefaults();
}
$enabled_rules = (array)($options['enabled_rules'] ?? null);
$dangerous_tags = (array)($options['dangerous_tags'] ?? null);
if (!$dangerous_tags) {
$enabled_rules['dangerous_tags'] = false;
}
$invalid_protocols = (array)($options['invalid_protocols'] ?? null);
if (!$invalid_protocols) {
$enabled_rules['invalid_protocols'] = false;
}
$enabled_rules = array_filter($enabled_rules, static function ($val) { return !empty($val); });
if (!$enabled_rules) {
return null;
}
// Keep a copy of the original string before cleaning up
$orig = $string;
// URL…
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-2026-42611 has been found in getgrav/grav.
Attackers can target a specific entry point like POST /grav-log over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.9/10.
What to do: upgrade getgrav/grav to 2.0.0-beta.2 or later.
If unsure, ask your IT team or search "getgrav/grav CVE-2026-42611" on the vendor's site.
CVE-2026-42611 (getgrav/grav) — CWE-79 / CVSS v3 8.9
Attack vector: remote (network-reachable)
Attack surface: POST /grav-log / svg / info / ncat
Patched: 2.0.0-beta.2 — 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 getgrav/grav. Attackers reach the vulnerable code path via POST /grav-log.
Check the vendor advisory for the affected versions of getgrav/grav. Attack surface: POST /grav-log / svg / info / ncat.
Severity: High (CVSS 8.9/10). Confidential information can be exposed externally.
Update to 2.0.0-beta.2.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /grav-log requests with malformed payloads or SQL meta-characters. Run grep -r 'getgrav/grav' . 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 'getgrav/grav' . | 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
getgrav/gravを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /grav-log' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /grav-logへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade getgrav/grav to 2.0.0-beta.2ステージング環境で 2.0.0-beta.2 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 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /grav-log on staging to confirm patch closes the vector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 2 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
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com