# CVE-2017-6791: Denial of service in Cisco Unified Communications Manager

> Unauthenticated remote attackers can cause a denial of service in Cisco Unified Communications Manager by sending incomplete TLS traffic streams.

- **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:** 7 Sep 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-5qmr-j946-m785

## What is CVE-2017-6791?

CVE-2017-6791 is a high-severity denial of service vulnerability in Cisco Unified Communications Manager, published on 7 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Trust Verification Service (TVS) of Cisco Unified Communications Manager could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of Transport Layer Security (TLS) traffic by the affected software. An attacker could exploit this vulnerability by generating incomplete traffic streams. A successful exploit could allow the attacker to deny access to the TVS for an affected device, resulting in a DoS condition, until an administrator restarts the service. Known Affected Releases 10.0(1.10000.24) 10.5(2.10000.5) 11.0(1.10000.10) 9.1(2.10000.28). Cisco Bug IDs: CSCux21905.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2017-6791?

It affects 1 product.


Products: Cisco Unified Communications Manager.

## How do I fix CVE-2017-6791?

No fix has been published for CVE-2017-6791 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-6791 being exploited?

There is no known exploitation of CVE-2017-6791 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Unified Communications Manager

- [CVE-2026-20230](https://insights.sbomify.com/CVE-2026-20230/): Cisco Unified Communications Manager Server-Side Request Forgery (SSRF) (high 8.6, exploited in the wild)
- [CVE-2026-20045](https://insights.sbomify.com/CVE-2026-20045/): Cisco Unified Communications Products Code Injection (high 8.2, exploited in the wild)
- [CVE-2025-20309](https://insights.sbomify.com/CVE-2025-20309/): Cisco Unified Communications Manager Static SSH Credentials Vulnerability (critical 10.0)
- [CVE-2011-1643](https://insights.sbomify.com/CVE-2011-1643/): Information disclosure in n/a (critical 10.0)
- [CVE-2024-20253](https://insights.sbomify.com/CVE-2024-20253/): Deserialization in Cisco Packaged Contact Center Enterprise (critical 9.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-6791 and fix it if it is affected.

What it is: CVE-2017-6791 is a high-severity denial of service vulnerability in Cisco Unified Communications Manager, published on 7 Sep 2017. 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-2017-6791 in the wild and no public exploit code.

Affected product: Cisco Unified Communications Manager. 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-2017-6791/ (Markdown: https://insights.sbomify.com/CVE-2017-6791/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-6791
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-6791
- OSV: https://osv.dev/vulnerability/CVE-2017-6791

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-6791/
Summaries are generated and may contain mistakes; the official description above is the record.