# CVE-2019-1635: Cisco IP Phone 7800 Series and 8800 Series Session Initiation Protocol XML Denial of Service Vulnerability

> Remote attackers can cause Cisco IP phones to reload unexpectedly by sending malicious SIP packets with crafted XML payloads.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 May 2019
- **Updated:** 19 Nov 2024
- **Also known as:** GHSA-mc83-gm47-m9vc

## What is CVE-2019-1635?

CVE-2019-1635 is a high-severity denial of service vulnerability in Cisco IP Phone 7800 Series and 8800 Series, published on 3 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the call-handling functionality of Session Initiation Protocol (SIP) Software for Cisco IP Phone 7800 Series and 8800 Series could allow an unauthenticated, remote attacker to cause an affected phone to reload unexpectedly, resulting in a temporary denial of service (DoS) condition. The vulnerability is due to incomplete error handling when XML data within a SIP packet is parsed. An attacker could exploit this vulnerability by sending a SIP packet that contains a malicious XML payload to an affected phone. A successful exploit could allow the attacker to cause the affected phone to reload unexpectedly, resulting in a temporary DoS condition.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions), CWE-399

## Which versions are affected by CVE-2019-1635?

It affects 16 products.


Products: Cisco Ip Conference Phone 7832 Firmware, Cisco Ip Conference Phone 8832 Firmware, Cisco Ip Phone 7811 Firmware, Cisco Ip Phone 7821 Firmware, Cisco Ip Phone 7841 Firmware, Cisco Ip Phone 7861 Firmware, Cisco Ip Phone 8811 Firmware, Cisco Ip Phone 8841 Firmware, Cisco Ip Phone 8845 Firmware, Cisco Ip Phone 8851 Firmware, Cisco Ip Phone 8861 Firmware, Cisco Ip Phone 8865 Firmware, Cisco Unified Ip 8831 Conference Phone1 Firmware, Cisco Unified Ip 8831 Conference Phone for Third-Party Call Control2 Firmware, Cisco Wireless Ip Phone 8821-Ex Firmware, Cisco Wireless Ip Phone 8821 Firmware.

## How do I fix CVE-2019-1635?

No fix has been published for CVE-2019-1635 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1635 being exploited?

There is no known exploitation of CVE-2019-1635 in the wild and no public exploit code.

## Other vulnerabilities in Cisco IP Phone 7800 Series and 8800 Series

- [CVE-2020-3111](https://insights.sbomify.com/CVE-2020-3111/): Cisco IP Phone Remote Code Execution and Denial of Service Vulnerability (high 8.8)
- [CVE-2021-1379](https://insights.sbomify.com/CVE-2021-1379/): Memory corruption in Cisco IP Phones with Multiplatform Firmware (medium 6.5)
- [CVE-2019-1684](https://insights.sbomify.com/CVE-2019-1684/): Denial of service in Cisco IP Phone 8800 Series Software (medium 6.5)
- [CVE-2021-34711](https://insights.sbomify.com/CVE-2021-34711/): Cisco IP Phone Software Arbitrary File Read Vulnerability (medium 5.5)
- [CVE-2019-1922](https://insights.sbomify.com/CVE-2019-1922/): Cisco IP Phone 7800 and 8800 Series Session Initiation Protocol Denial of Service Vulnerability (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-1635 and fix it if it is affected.

What it is: CVE-2019-1635 is a high-severity denial of service vulnerability in Cisco IP Phone 7800 Series and 8800 Series, published on 3 May 2019. 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-2019-1635 in the wild and no public exploit code.

Affected product: Cisco IP Phone 7800 Series and 8800 Series. 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-2019-1635/ (Markdown: https://insights.sbomify.com/CVE-2019-1635/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1635
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1635
- OSV: https://osv.dev/vulnerability/CVE-2019-1635

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-1635/
Summaries are generated and may contain mistakes; the official description above is the record.