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Mallory
Medium

Stored XSS in Foxit PDF Online Layer Import (Create new Layer)

IdentifiersCVE-2025-66519CWE-79· Improper Neutralization of Input…

A stored cross-site scripting (XSS) vulnerability exists in pdfonline.foxit.com within the Layer Import functionality. An attacker can inject a crafted script payload into the “Create new Layer” field during layer import; the value is later rendered into the DOM without proper sanitization/encoding. When a user accesses the Layers panel, the stored payload is inserted into the page and executes in the context of the pdfonline.foxit.com origin.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation results in arbitrary JavaScript execution in victims’ browsers under the pdfonline.foxit.com origin when the Layers panel is accessed. This can enable session/token theft, account actions as the victim, data exfiltration from the application context, and other same-origin impacts typical of stored XSS.

Mitigation

If you can’t patch tonight, do this now.

Until patched, reduce exposure by restricting access to the affected Layer Import feature to trusted users, and deploy/strengthen a restrictive Content Security Policy (CSP) to limit script execution (e.g., disallow inline/eval and restrict script-src). Monitor for suspicious layer names/payload patterns and consider WAF rules to block common XSS payloads targeting the relevant parameter/field.

Remediation

Patch, then assume compromise.

Apply the vendor-provided fix for CVE-2025-66519. Ensure the “Create new Layer” field is properly sanitized and/or contextually output-encoded before insertion into the DOM, and avoid unsafe DOM sinks (e.g., innerHTML/dangerouslySetInnerHTML) for untrusted content. Add server-side validation to prevent persistence of script-capable markup.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Foxit SoftwarePdf Editor Cloudapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.