# CVE-2020-26070: Denial of service in Cisco IOS XR Software

> Remote unauthenticated attackers can cause a denial of service on Cisco ASR 9000 routers by exhausting buffer resources via specific network traffic.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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:** 12 Nov 2020
- **Updated:** 13 Nov 2024
- **Also known as:** GHSA-wg72-p7jc-jqrx

## What is CVE-2020-26070?

CVE-2020-26070 is a high-severity denial of service vulnerability in Cisco Ios Xr, published on 12 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the ingress packet processing function of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper resource allocation when an affected device processes network traffic in software switching mode (punted). An attacker could exploit this vulnerability by sending specific streams of Layer 2 or Layer 3 protocol data units (PDUs) to an affected device. A successful exploit could cause the affected device to run out of buffer resources, which could make the device unable to process or forward traffic, resulting in a DoS condition. The device would need to be restarted to regain functionality.

Weakness: CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2020-26070?

It affects 1 product.


Products: Cisco Ios Xr.

## How do I fix CVE-2020-26070?

No fix has been published for CVE-2020-26070 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-26070 being exploited?

There is no known exploitation of CVE-2020-26070 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios Xr

- [CVE-2020-3118](https://insights.sbomify.com/CVE-2020-3118/): Cisco IOS XR Software Discovery Protocol Format String (high 8.8, exploited in the wild)
- [CVE-2020-3569](https://insights.sbomify.com/CVE-2020-3569/): Cisco IOS XR Software DVMRP Memory Exhaustion (high 8.6, exploited in the wild)
- [CVE-2020-3566](https://insights.sbomify.com/CVE-2020-3566/): Cisco IOS XR Software DVMRP Memory Exhaustion (high 8.6, exploited in the wild)
- [CVE-2010-3035](https://insights.sbomify.com/CVE-2010-3035/): Cisco IOS XR Border Gateway Protocol (BGP) Denial-of-Service (high 7.5, exploited in the wild)
- [CVE-2022-20821](https://insights.sbomify.com/CVE-2022-20821/): Cisco IOS XR Open Port (medium 6.5, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-26070 and fix it if it is affected.

What it is: CVE-2020-26070 is a high-severity denial of service vulnerability in Cisco Ios Xr, published on 12 Nov 2020. 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-2020-26070 in the wild and no public exploit code.

Affected product: Cisco Ios Xr. 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-2020-26070/ (Markdown: https://insights.sbomify.com/CVE-2020-26070/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-26070
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-26070
- OSV: https://osv.dev/vulnerability/CVE-2020-26070

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-26070/
Summaries are generated and may contain mistakes; the official description above is the record.