# CVE-2009-2726: Denial of service in n/a

> Remote attackers can cause denial of service in Asterisk PBX by sending SIP packets with large sequences of ASCII decimal characters.

- **Severity:** High 7.8 (`AV:N/AC:L/Au:N/C:N/I:N/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Aug 2009
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2009-2726, GHSA-9w42-v5mm-2ffh

## What is CVE-2009-2726?

CVE-2009-2726 is a high-severity denial of service vulnerability in Digium Asterisk, published on 12 Aug 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2009-2726?

It affects 2 products.


Products: Digium Asterisk, Digium S800i Firmware.

## How do I fix CVE-2009-2726?

Upgrade to a fixed version.

## Is CVE-2009-2726 being exploited?

There is no known exploitation of CVE-2009-2726 in the wild and no public exploit code.

## Other vulnerabilities in Digium Asterisk

- [CVE-2017-14100](https://insights.sbomify.com/CVE-2017-14100/): Command injection in n/a (critical 9.8)
- [CVE-2014-8418](https://insights.sbomify.com/CVE-2014-8418/): Privilege escalation in n/a (critical 9.0)
- [CVE-2011-1599](https://insights.sbomify.com/CVE-2011-1599/): Missing authorization in n/a (critical 9.0)
- [CVE-2017-16671](https://insights.sbomify.com/CVE-2017-16671/): Memory corruption in n/a (high 8.8)
- [CVE-2017-7617](https://insights.sbomify.com/CVE-2017-7617/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2009-2726 and fix it if it is affected.

What it is: CVE-2009-2726 is a high-severity denial of service vulnerability in Digium Asterisk, published on 12 Aug 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2009-2726 in the wild and no public exploit code.

Affected product: Digium Asterisk. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2009-2726/ (Markdown: https://insights.sbomify.com/CVE-2009-2726/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-2726
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-2726
- OSV: https://osv.dev/vulnerability/CVE-2009-2726

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-2726/
Summaries are generated and may contain mistakes; the official description above is the record.