# CVE-2026-26266: AliasVault affected by Cross-Site Scripting (XSS) via Email HTML Rendering

> Attackers can execute arbitrary JavaScript in the victim's browser by sending crafted emails, potentially leading to account takeover.

- **Severity:** Critical 9.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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:** 3 Mar 2026
- **Updated:** 4 Mar 2026
- **Also known as:** GHSA-f65p-p65r-g53q

## What is CVE-2026-26266?

CVE-2026-26266 is a critical cross-site scripting vulnerability in aliasvault, published on 3 Mar 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. A stored cross-site scripting (XSS) vulnerability was identified in the email rendering feature of AliasVault Web Client versions 0.25.3 and lower. When viewing received emails on an alias, the HTML content is rendered in an iframe using srcdoc, which does not provide origin isolation. An attacker can send a crafted email containing malicious JavaScript to any AliasVault email alias. When the victim views the email in the web client, the script executes in the same origin as the application. No sanitization or sandboxing was applied to email HTML content before rendering. This vulnerability is fixed in 0.26.0.[

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-26266?

It affects 1 product.


Products: Aliasvault Aliasvault.

## How do I fix CVE-2026-26266?

No fix has been published for CVE-2026-26266 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-26266 being exploited?

There is no known exploitation of CVE-2026-26266 in the wild and no public exploit code.

## Other vulnerabilities in aliasvault

- [CVE-2026-22694](https://insights.sbomify.com/CVE-2026-22694/): AliasVault is Missing Origin Validation in Android Passkey Credential Provider (medium 6.1)
- [CVE-2026-2974](https://insights.sbomify.com/CVE-2026-2974/): AliasVault App Backup aliasvault.xml backup (low 2.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-26266 and fix it if it is affected.

What it is: CVE-2026-26266 is a critical cross-site scripting vulnerability in aliasvault, published on 3 Mar 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-2026-26266 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-2026-26266/ (Markdown: https://insights.sbomify.com/CVE-2026-26266/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-26266
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26266
- OSV: https://osv.dev/vulnerability/CVE-2026-26266

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-26266/
Summaries are generated and may contain mistakes; the official description above is the record.