---
id: "CVE-2026-121451"
kind: "vulnerability"
aliases: ["CVE-2026-121451"]
title: "AB Download Manager: web pages can write files to any path"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ab-download-manager", "browser-integration", "desktop", "package", "windows"]
not_affected_if: ["browser-integration-disabled", "version-1.11.2-or-later"]
published_at: "2026-11-03T16:17:23+00:00"
first_seen_at: "2026-11-03T16:21:43+00:00"
updated_at: "2026-11-03T16:23:37+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121451", "first_seen_at": "2026-11-03T16:21:43+00:00"}]
---

# AB Download Manager: web pages can write files to any path

AB Download Manager before 1.11.2 accepts unauthenticated requests from its browser integration API, so a malicious web page can make the user's browser send a request that writes attacker-chosen files to arbitrary paths. An attacker can place payloads in startup folders to run code on the next login.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed AB Download Manager version in its About screen or package metadata; versions below `1.11.2` are in scope.
- Confirm whether the browser integration API is enabled on the machine.

## Fix

- AB Download Manager: `1.11.2` or later (per the advisory range 'before 1.11.2').

## Timeline

- 2026-11-03T16:21:43+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121451

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ab-download-manager-before-1.11.2-arbitrary-file-write-via-start-headless-download-csrf
- [fix] Patch: github.com https://github.com/amir1376/ab-download-manager/commit/34cd27af6a9a6c2046af112bc9bd34828fec0bbc

## From the sources

AB Download Manager before 1.11.2 contains a cross-site request forgery vulnerability in its unauthenticated browser-integration API that allows remote attackers to write attacker-chosen files to arbitrary paths. A malicious web page can send a text/plain request to /start-headless-download with crafted folder and name values, placing payloads in startup folders for code execution on next login.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_