---
id: "CVE-2026-57199"
kind: "vulnerability"
aliases: ["CVE-2026-57199"]
title: "Asterisk: SMS dialplan application overflows buffers, allowing memory corruption or crash"
severity: "low"
cvss: 2.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["asterisk", "package", "self-hosted", "telephony"]
not_affected_if: ["default-config", "sms-application-unused"]
published_at: "2026-10-27T22:17:27+00:00"
first_seen_at: "2026-10-27T22:29:29+00:00"
updated_at: "2026-10-27T22:30:17+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-57199", "first_seen_at": "2026-10-27T22:29:29+00:00"}]
---

# Asterisk: SMS dialplan application overflows buffers, allowing memory corruption or crash

Asterisk's app_sms.c copies externally controlled SMS lengths into fixed in-struct buffers without enough bounds checks. An attacker who can feed data into the SMS dialplan application can corrupt memory or crash Asterisk.

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

## How to check

- Search the dialplan for the `SMS` application (for example with `grep -rn "SMS(" /etc/asterisk/`)
- Confirm the running version with `asterisk -rx "core show version"`

## 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`
- Until upgraded, remove or stop using the `SMS` dialplan application

## Timeline

- 2026-10-27T22:29:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-57199

## 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, `app_sms.c` copies externally controlled `SMS` lengths into `fixed in-struct buffers` without sufficient bounds checks, allowing an attacker to corrupt memory or crash Asterisk. The administrator must explicitly use the `SMS` dialplan application, which is useful when routing calls to or from `analog devices`, and must not have ensured that data passed to the application is valid. 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.

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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_