CVE Catalog

CVE-2026-54565

MediumCVSS 4.7
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.19%

8th percentile - higher than 8% of all known CVEs

Summary

rhwp is an HWP viewer and editor implemented in Rust and WebAssembly. The browser extensions use an all-URLs host permission to detect HWP and HWPX links, but the service workers do not validate message senders, URL schemes, or destination addresses before privileged fetches. An untrusted page can make the fetch-file and extract-thumbnail handlers request localhost or private-network resources. When a target HWP or HWPX file contains an extractable PrvImage, the extension returns the preview as a data URI in page-readable DOM, allowing page script to read it. This issue is fixed in rhwp 0.7.15 and rhwp Chrome and Firefox extension 0.2.4.

Risk Assessment

A malicious page can probe internal resources and ports, exfiltrate image previews from HWP/HWPX files, and fingerprint extension presence and version. Exploitation requires visiting an untrusted page with the extension enabled.

Recommendation

Update rhwp to version 0.7.15 and the Chrome and Firefox extensions to version 0.2.4. Inform users about the risk of visiting untrusted pages with the extension enabled.

Related vulnerabilities

Original NVD description (English source)

rhwp is an HWP viewer and editor implemented in Rust and WebAssembly. Prior to rhwp 0.7.15 and rhwp Chrome and Firefox extension 0.2.4, the browser extensions use an all-URLs host permission to detect HWP and HWPX links on visited pages, but the service workers do not validate message senders, URL schemes, or destination addresses before privileged fetches. The affected paths are rhwp-chrome/manifest.json, rhwp-chrome/content-script.js, rhwp-chrome/sw/message-router.js, rhwp-chrome/sw/thumbnail-extractor.js, rhwp-firefox/manifest.json, rhwp-firefox/content-script.js, rhwp-firefox/sw/message-router.js, and rhwp-firefox/sw/thumbnail-extractor.js. An untrusted page can make the fetch-file and extract-thumbnail handlers request localhost or private-network resources. When a target HWP or HWPX file contains an extractable PrvImage, the extension returns the preview as a data URI in page-readable DOM, allowing page script to read it. The flaw also permits internal-resource existence and port probing and extension presence or version fingerprinting. Exploitation requires a user to visit an untrusted page while the extension is enabled, and preview disclosure is limited to an extractable PrvImage. This issue is fixed in rhwp 0.7.15 and rhwp Chrome and Firefox extension 0.2.4.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS