# CVE-2026-44659: Zen Browser Mac - Address Bar Spoofing via Long Subdomain

> Attackers can spoof the address bar using long subdomains to mislead users about the site's origin, facilitating phishing attacks.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/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:** 11 May 2026
- **Updated:** 12 May 2026
- **Also known as:** GHSA-7p2r-fp29-9w69

## What is CVE-2026-44659?

CVE-2026-44659 is a medium-severity vulnerability in zen-browser desktop, published on 11 May 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

Zen is a firefox-based browser. Prior to 1.19.12b, the ZEN Browser incorrectly truncates long hostnames in the address bar and shows only the attacker-controlled prefix of the subdomain, hiding the actual registrable domain (eTLD+1). As a result, an attacker can craft extremely long malicious subdomains that visually imitate trusted brands, and the browser will display only the spoofed prefix, misleading users about the actual origin of the site. This directly compromises the URL bar as a security indicator and creates a phishing/supply-chain attack vector. This vulnerability is fixed in 1.19.12b.

Weakness: CWE-451 (User Interface (UI) Misrepresentation of Critical Information)

## Which versions are affected by CVE-2026-44659?


## How do I fix CVE-2026-44659?

No fix has been published for CVE-2026-44659 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-44659 being exploited?

There is no known exploitation of CVE-2026-44659 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44659 and fix it if it is affected.

What it is: CVE-2026-44659 is a medium-severity vulnerability in zen-browser desktop, published on 11 May 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-2026-44659 in the wild and no public exploit code.

Affected product: zen-browser desktop. 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-2026-44659/ (Markdown: https://insights.sbomify.com/CVE-2026-44659/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44659
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44659
- OSV: https://osv.dev/vulnerability/CVE-2026-44659

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44659/
Summaries are generated and may contain mistakes; the official description above is the record.