---
id: "CVE-2026-57189"
kind: "vulnerability"
aliases: ["CVE-2026-57189"]
title: "Asterisk: T.140 RED out-of-bounds write via chan_sip text support"
severity: "low"
cvss: 2.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["asterisk", "package", "pbx", "sip", "voip"]
not_affected_if: ["chan-sip-not-loaded", "pjsip-only", "textsupport-disabled"]
published_at: "2026-10-27T17:17:01+00:00"
first_seen_at: "2026-10-27T17:32:46+00:00"
updated_at: "2026-10-27T17:35:05+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-57189", "first_seen_at": "2026-10-27T17:32:46+00:00"}]
---

# Asterisk: T.140 RED out-of-bounds write via chan_sip text support

An authenticated attacker can send crafted packets that cause an out-of-bounds write in Asterisk's T.140 RED text handling during generation accumulation. The write can lead to remote code execution or crash Asterisk.

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

## How to check

- Run `asterisk -rx "module show like chan_sip"` to see whether chan_sip is loaded
- Check sip.conf for `textsupport=yes` in the relevant peer or general section (default is no)
- Confirm the installed release against the fixed versions listed in the fix

## Fix

- Upgrade Asterisk 20 to `20.20.1` or later, Asterisk 21 to `21.12.3`, Asterisk 22 to `22.10.1`, Asterisk 23 to `23.4.1`
- Certified Asterisk: move to `20.7-cert11` or `22.8-cert3`
- If chan_sip is not needed, leave `textsupport` at no or stop loading chan_sip

## Timeline

- 2026-10-27T17:32:46+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-57189

## From the sources

Asterisk is an open source private branch exchange and telephony toolkit. In affected deployments, an authenticated attacker may cause a `T.140 RED` out-of-bounds write during `generation accumulation` using carefully crafted packets, potentially allowing remote code execution or causing Asterisk to crash. The `chan_sip` channel driver must be installed and configured, and its `textsupport` option must be enabled; `textsupport` defaults to no. `The chan_sip driver was deprecated in Asterisk 20 and completely removed in all later versions.` Repository comparisons verify patch containment in Asterisk 20.20.1, 21.12.3, 22.10.1 and 23.4.1, and Certified Asterisk 20.7-cert11 and 22.8-cert3. The affected release-track scope remains unresolved: structured metadata includes later release tracks even though the advisory says the required `chan_sip` driver was removed there.

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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_