# CVE-2026-54565: rhwp browser extension performs SSRF / private-network requests and leaks HWP preview data to untrusted pages

> An untrusted page can trigger the rhwp extension to fetch private network resources and leak HWP preview data, requiring an upgrade to the latest version.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-j972-m9fh-g22m

## What is CVE-2026-54565?

CVE-2026-54565 is a medium-severity server-side request forgery vulnerability in edwardkim rhwp, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

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.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-359 (Exposure of Private Personal Information to an Unauthorized Actor), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), CWE-1385 (Missing Origin Validation in WebSockets)

## Which versions are affected by CVE-2026-54565?


## How do I fix CVE-2026-54565?

No fix has been published for CVE-2026-54565 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54565 being exploited?

There is no known exploitation of CVE-2026-54565 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54565 and fix it if it is affected.

What it is: CVE-2026-54565 is a medium-severity server-side request forgery vulnerability in edwardkim rhwp, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-54565 in the wild and no public exploit code.

Affected product: edwardkim rhwp. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-54565/ (Markdown: https://insights.sbomify.com/CVE-2026-54565/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54565
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54565
- OSV: https://osv.dev/vulnerability/CVE-2026-54565

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54565/
Summaries are generated and may contain mistakes; the official description above is the record.