# CVE-2020-6881: Denial of service in > Remote attackers can cause denial of service on ZTE routers by sending malformed MQTT messages due to insufficient input validation. - **Severity:** High 7.5 (`CVSS:3.1/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:** 21 Dec 2020 - **Updated:** 4 Aug 2024 - **Also known as:** GHSA-f6c6-g5xq-fvm6 ## What is CVE-2020-6881? CVE-2020-6881 is a high-severity denial of service vulnerability in , published on 21 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description ZTE E8810/E8820/E8822 series routers have an MQTT DoS vulnerability, which is caused by the failure of the device to verify the validity of abnormal messages. A remote attacker could connect to the MQTT server and send an MQTT exception message to the specified device, which will cause the device to deny service. This affects: Weakness: CWE-346 (Origin Validation Error) ## Which versions are affected by CVE-2020-6881? It affects 3 products. Products: Zte Zxhn E8810 Firmware, Zte Zxhn E8820 Firmware, Zte Zxhn E8822 Firmware. ## How do I fix CVE-2020-6881? No fix has been published for CVE-2020-6881 yet. Limit exposure of the affected software until one is available. ## Is CVE-2020-6881 being exploited? There is no known exploitation of CVE-2020-6881 in the wild and no public exploit code. ## Other vulnerabilities in - [CVE-2020-6882](https://insights.sbomify.com/CVE-2020-6882/): Hardcoded credentials in (high 7.5) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-6881 and fix it if it is affected. What it is: CVE-2020-6881 is a high-severity denial of service vulnerability in , published on 21 Dec 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-2020-6881 in the wild and no public exploit code. Affected product: . 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-2020-6881/ (Markdown: https://insights.sbomify.com/CVE-2020-6881/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-6881 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-6881 - OSV: https://osv.dev/vulnerability/CVE-2020-6881 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-6881/ Summaries are generated and may contain mistakes; the official description above is the record.