---
id: "CVE-2026-57198"
kind: "vulnerability"
aliases: ["CVE-2026-57198"]
title: "Asterisk: crafted T.140 RED packets overflow heap buffer via chan_sip"
severity: "low"
cvss: 2.3
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["asterisk", "runtime", "self-hosted", "sip", "telephony"]
not_affected_if: ["chan-sip-not-configured", "textsupport-default-no"]
published_at: "2026-10-27T17:17:01+00:00"
first_seen_at: "2026-10-27T17:32:46+00:00"
updated_at: "2026-10-27T17:35:09+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-57198", "first_seen_at": "2026-10-27T17:32:46+00:00"}]
---

# Asterisk: crafted T.140 RED packets overflow heap buffer via chan_sip

Asterisk's chan_sip driver has a heap buffer overflow in T.140 RED text handling, triggered by specially crafted packets. An authenticated attacker may be able to run code on the server or crash Asterisk.

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

## How to check

- Run `asterisk -V` to get the installed version.
- Check whether chan_sip is loaded and configured, for example with `asterisk -rx "module show like chan_sip"`.
- Check whether `textsupport` is set to yes in the chan_sip configuration.

## Fix

- Move to a patched release: `20.20.1`, `21.12.3`, `22.10.1` or `23.4.1`, or Certified Asterisk `20.7-cert11` or `22.8-cert3`.
- If chan_sip is in use, keep `textsupport` at its default of `no` until patched.

## Timeline

- 2026-10-27T17:32:46+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-57198

## 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` heap buffer overflow 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_