# CVE-2025-20142: Cisco IOS XR Software for ASR 9000 Series Routers L2VPN Denial of Service Vulnerability > Remote attackers can cause line card resets and traffic loss on Cisco ASR routers by sending malformed IPv4 packets to interfaces with ACLs or QoS policies. - **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 Mar 2025 - **Updated:** 21 Mar 2025 - **Also known as:** GHSA-w9ff-5p26-w67v ## What is CVE-2025-20142? CVE-2025-20142 is a high-severity denial of service vulnerability in Cisco Ios Xr, published on 12 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description A vulnerability in the IPv4 access control list (ACL) feature and quality of service (QoS) policy feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of malformed IPv4 packets that are received on line cards where the interface has either an IPv4 ACL or QoS policy applied. An attacker could exploit this vulnerability by sending crafted IPv4 packets through an affected device. A successful exploit could allow the attacker to cause network processor errors, resulting in a reset or shutdown of the network process. Traffic over that line card would be lost while the line card reloads. Note: This vulnerability has predominantly been observed in Layer 2 VPN (L2VPN) environments where an IPv4 ACL or QoS policy has been applied to the bridge virtual interface. Layer 3 configurations where the interface has either an IPv4 ACL or QoS policy applied are also affected, though the vulnerability has not been observed. Weakness: CWE-20 (Improper Input Validation) ## Which versions are affected by CVE-2025-20142? It affects 1 product. Products: Cisco Ios Xr. ## How do I fix CVE-2025-20142? No fix has been published for CVE-2025-20142 yet. Limit exposure of the affected software until one is available. ## Is CVE-2025-20142 being exploited? There is no known exploitation of CVE-2025-20142 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-2025-20142 and fix it if it is affected. What it is: CVE-2025-20142 is a high-severity denial of service vulnerability in Cisco Ios Xr, published on 12 Mar 2025. 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-2025-20142 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-2025-20142/ (Markdown: https://insights.sbomify.com/CVE-2025-20142/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-20142 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-20142 - OSV: https://osv.dev/vulnerability/CVE-2025-20142 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-20142/ Summaries are generated and may contain mistakes; the official description above is the record.