---
id: "CVE-2026-57202"
kind: "vulnerability"
aliases: ["CVE-2026-57202"]
title: "Asterisk: read-only ARI user can write files through setChannelVar"
severity: "high"
cvss: 8.1
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["asterisk", "package", "pbx", "self-hosted", "telephony"]
not_affected_if: ["ari-disabled", "default-config", "http-disabled"]
published_at: "2026-10-27T18:17:37+00:00"
first_seen_at: "2026-10-27T18:33:00+00:00"
updated_at: "2026-10-27T18:34:28+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-57202", "first_seen_at": "2026-10-27T18:33:00+00:00"}]
---

# Asterisk: read-only ARI user can write files through setChannelVar

Asterisk's REST Interface lets a user with read-only ARI credentials call setChannelVar to run write dialplan functions, including FILE() writes, even when live_dangerously is set to no. An attacker who holds those credentials can write files on the Asterisk host, which can lead to code execution.

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

## How to check

- Run `asterisk -V` to read the installed version.
- Check `asterisk.conf` for `live_dangerously`, and check whether the HTTP server is enabled in `http.conf` and bound to a reachable address.
- Check `ari.conf` for read-only ARI users.

## Fix

- Upgrade Asterisk to `20.20.1`, `21.12.3`, `22.10.1` or `23.4.1`.
- Upgrade Certified Asterisk to `20.7-cert11` or `22.8-cert3`.

## Timeline

- 2026-10-27T18:33:00+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-57202

## From the sources

Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an authenticated Asterisk REST Interface (ARI) attacker with read-only privileges may use `setChannelVar` to execute write dialplan functions, including `FILE()` writes, even when `live_dangerously` in `asterisk.conf` is set to no. The Asterisk HTTP web server must be enabled and reachable, and the attacker must already have valid `read-only ARI credentials`. HTTP is disabled by default and binds only to 127.0.0.1 by default even when enabled. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.

---

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