Apostrophe has stored XSS via javascript: URL in Image Widget Link

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

ApostropheCMS is an open-source Node.js content management system. Version 4.29.0 has a stored cross-site scripting vulnerability in the image widget functionality. A user with the Editor role can configure an image widget link to use a javascript: URL payload. Because editors have permission to publish pages, the malicious widget can be published to the live site. When another user, including an administrator or public visitor, clicks the affected image/link, arbitrary JavaScript executes in the victim’s browser. As of time of publication, no known patched versions are available.

Source published

12 Jun 2026 20:43:18 UTC

Source modified

15 Jun 2026 15:16:38 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

ApostropheCMS is an open-source Node.js content management system. Version 4.29.0 has a stored cross-site scripting vulnerability in the image widget functionality. A user with the Editor role can configure an image widget link to use a javascript: URL payload. Because editors have permission to publish pages, the malicious widget can be published to the live site. When another user, including an administrator or public visitor, clicks the affected image/link, arbitrary JavaScript executes in the victim’s browser. As of time of publication, no known patched versions are available.

Source published

Jun 12, 2026, 8:43:18 PM (timezone not stated)

Source modified

Jun 15, 2026, 3:16:38 PM (timezone not stated)

Observed here

7 Nov 2026 10:33:16 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

ApostropheCMS is an open-source Node.js content management system. Version 4.29.0 has a stored cross-site scripting vulnerability in the image widget functionality. A user with the Editor role can configure an image widget link to use a javascript: URL payload. Because editors have permission to publish pages, the malicious widget can be published to the live site. When another user, including an administrator or public visitor, clicks the affected image/link, arbitrary JavaScript executes in the victim’s browser. As of time of publication, no known patched versions are available.

Source published

12 Jun 2026 21:16:22 UTC

Source modified

26 Oct 2026 11:10:00 UTC

Observed here

27 Oct 2026 11:12:23 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

### Summary A stored cross-site scripting vulnerability was identified in the image widget functionality. A user with the Editor role can configure an image widget link to use a javascript: URL payload. Because editors have permission to publish pages, the malicious widget can be published to the live site. When another user, including an administrator or public visitor, clicks the affected image/link, arbitrary JavaScript executes in the victim’s browser. ### Affected Version ApostropheCMS (tested on version: v4.29.0) ### Steps to Reproduce **Precondition** Ensure at least one image exists in the media library. If the media library is empty: - Log in as an Editor. - Open the media library. - Upload any JPG or PNG image. - Set any title, for example Probe image. - Publish the image and close the media manager. **Exploitation Steps** - Log in as an Editor. - Open the home page. - Enable edit mode for the page. - In the main content area, click Add content. - Select the Image widget. - Choose any existing image from the image picker and save/select it. - Open the image widget settings. - Locate the Link to field and change it to URL. - In the URL field, enter: ```javascript:alert(document.domain)``` <img width="1249" height="979" alt="image" src="https://github.com/user-attachments/assets/c7f77177-1711-461d-b9bd-14292a6996d5" /> - Save the image and click on Update. - As another user, such as an administrator or guest, open the published page and click the linked image. - Observe that the JavaScript payload executes. <img width="1267" height="1034" alt="image" src="https://github.com/user-attachments/assets/a80484b4-873a-47c1-8682-84626523008a" /> **Note**: This attack can also be performed by a Contributor. However, because contributors cannot publish content directly, the malicious image widget remains in the draft version and is only visible to users with access to review drafts, such as administrators or editors. If an administrator reviews and approves/publishes the affected draft, the stored XSS becomes part of the live page and can then affect all users who interact with the malicious image link. ### Impact Successful exploitation allows an Editor to store a JavaScript payload in published page content. When a victim clicks the affected image link, the payload executes in the victim’s browser. This may allow an attacker to: - perform actions in the context of an authenticated administrator - access sensitive information available in the CMS interface - modify page content or configuration - conduct phishing attacks within the trusted site - compromise visitors who interact with the published image link ### Recommendation Validate and sanitize all user-supplied URLs used in widget link fields. Specifically: - Reject dangerous URL schemes such as javascript:, data:, and other executable schemes. - Allow only safe protocols such as http:, https:, mailto:, and relative URLs where appropriate. - Normalize and validate URLs server-side before storage. - Encode rendered URLs safely in templates. - Consider applying a strict Content Security Policy to reduce the impact of XSS.

Source published

14 May 2026 18:27:56 UTC

Source modified

12 Jun 2026 22:15:10 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

Publisher rating · HIGH