# CVE-2026-55587: AliasVault: Browser extension WebAuthn bridge accepts forged origin/RP ID

> A malicious website can forge origin and relying-party values to obtain valid passkey assertions for other sites if the user approves the prompt.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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:** 15 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** GHSA-f99p-jfhr-6ffc

## What is CVE-2026-55587?

CVE-2026-55587 is a high-severity vulnerability in aliasvault, published on 15 Oct 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

AliasVault is a privacy-first password manager with built-in email aliasing. Prior to 0.29.4, the AliasVault browser extension passkey provider does not bind passkey requests to the actual webpage origin or verify that the requested relying-party identifier matches the current website. A malicious website can provide forged origin and relying-party values and, if a victim with a matching stored passkey approves the AliasVault passkey prompt, obtain a valid assertion for a different website. Exploitation requires the extension to be installed, unlocked, and configured as a passkey provider, requires a stored passkey for the impersonated site, and cannot occur silently because the victim must approve the prompt. The server, web application, and mobile applications are not affected. This issue is fixed in version 0.29.4.

Weakness: CWE-346 (Origin Validation Error)

## Which versions are affected by CVE-2026-55587?


## How do I fix CVE-2026-55587?

No fix has been published for CVE-2026-55587 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55587 being exploited?

There is no known exploitation of CVE-2026-55587 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55587 and fix it if it is affected.

What it is: CVE-2026-55587 is a high-severity vulnerability in aliasvault, published on 15 Oct 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-2026-55587 in the wild and no public exploit code.

Affected product: aliasvault. 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-2026-55587/ (Markdown: https://insights.sbomify.com/CVE-2026-55587/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55587
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55587
- OSV: https://osv.dev/vulnerability/CVE-2026-55587

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55587/
Summaries are generated and may contain mistakes; the official description above is the record.