# CVE-2021-21723: Denial of service in > Remote attackers can cause a denial of service on ZTE ZXR10 switches by triggering a memory leak through specific operations. - **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 Jan 2021 - **Updated:** 3 Aug 2024 - **Also known as:** GHSA-7h22-x3wx-hv9p ## What is CVE-2021-21723? CVE-2021-21723 is a high-severity denial of service vulnerability in , published on 21 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Some ZTE products have a DoS vulnerability. Due to the improper handling of memory release in some specific scenarios, a remote attacker can trigger the vulnerability by performing a series of operations, resulting in memory leak, which may eventually lead to device denial of service. This affects: ZXR10 9904, ZXR10 9908, ZXR10 9916, ZXR10 9904-S, ZXR10 9908-S; all versions up to V1.01.10.B12. Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime) ## Which versions are affected by CVE-2021-21723? It affects 5 products. Products: Zte Zxr10 9904-S Firmware, Zte Zxr10 9904 Firmware, Zte Zxr10 9908-S Firmware, Zte Zxr10 9908 Firmware, Zte Zxr10 9916 Firmware. ## How do I fix CVE-2021-21723? No fix has been published for CVE-2021-21723 yet. Limit exposure of the affected software until one is available. ## Is CVE-2021-21723 being exploited? There is no known exploitation of CVE-2021-21723 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-21723 and fix it if it is affected. What it is: CVE-2021-21723 is a high-severity denial of service vulnerability in , published on 21 Jan 2021. 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-2021-21723 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-2021-21723/ (Markdown: https://insights.sbomify.com/CVE-2021-21723/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21723 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21723 - OSV: https://osv.dev/vulnerability/CVE-2021-21723 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-21723/ Summaries are generated and may contain mistakes; the official description above is the record.