{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-0239 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-0239 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-0239 is a medium-severity denial of service vulnerability in Juniper Junos Os Evolved, published on 22 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-0239 and fix it if it is affected.\n\nWhat it is: CVE-2021-0239 is a medium-severity denial of service vulnerability in Juniper Junos Os Evolved, published on 22 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-0239 in the wild and no public exploit code.\n\nAffected product: Juniper Junos Os Evolved. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. 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.\n2. 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.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-0239/ (Markdown: https://insights.sbomify.com/CVE-2021-0239/index.md)","id":"CVE-2021-0239","markdown":"https://insights.sbomify.com/CVE-2021-0239/index.md","name":"CVE-2021-0239","record":{"aliases":["GHSA-hr3q-mvqf-hmmc"],"analysis":{"component_type":"network_device","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Juniper network OS","requires_auth":"none","summary":"An attacker can cause a sustained Denial of Service by sending specific Layer 2 frames that crash the packet forwarding engine in Junos OS Evolved.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"juniper","cpe":[{"product":"junos_os_evolved","vendor":"juniper"}],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-754","name":"Improper Check for Unusual or Exceptional Conditions"}],"description":"In Juniper Networks Junos OS Evolved, receipt of a stream of specific genuine Layer 2 frames may cause the Advanced Forwarding Toolkit (AFT) manager process (Evo-aftmand), responsible for handling Route, Class-of-Service (CoS), Firewall operations within the packet forwarding engine (PFE) to crash and restart, leading to a Denial of Service (DoS) condition. By continuously sending this specific stream of genuine Layer 2 frames, an attacker can repeatedly crash the PFE, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R1-EVO. This issue does not affect Junos OS versions.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":null,"headline":"Junos OS Evolved: Denial of Service due to receipt of specific genuine layer 2 frames.","id":"CVE-2021-0239","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"juniper:junos_os_evolved","products":["juniper:junos_os_evolved"],"type":"denial_of_service","year":"2021"},"n_packages":0,"n_references":1,"next":{"headline":"Junos OS: Receipt of malformed DHCPv6 packets causes jdhcpd to crash and restart.","id":"CVE-2021-0240"},"packages":[],"prev":{"headline":"Junos OS: MX Series: Executing CLI command repetitively may cause the system to run out of disk space","id":"CVE-2021-0238"},"products":["Junos OS Evolved"],"published":"2021-04-22","related":[{"cvss_score":9.3,"headline":"Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root","id":"CVE-2026-21902","kev_date_added":null,"published":"2026-02-25"},{"cvss_score":8.8,"headline":"Junos OS Evolved: Shell Injection vulnerability in the gNOI server","id":"CVE-2023-28983","kev_date_added":null,"published":"2023-04-17"},{"cvss_score":8.7,"headline":"Denial of service in Junos OS Evolved","id":"CVE-2025-21599","kev_date_added":null,"published":"2025-01-09"},{"cvss_score":8.7,"headline":"Junos OS Evolved: TCP session state is not always cleared on the Routing Engine leading to DoS","id":"CVE-2024-47502","kev_date_added":null,"published":"2024-10-11"},{"cvss_score":8.7,"headline":"Junos OS Evolved: ACX 7000 Series: Protocol specific DDoS configuration affects other protocols","id":"CVE-2024-39531","kev_date_added":null,"published":"2024-07-11"},{"cvss_score":8.7,"headline":"Junos OS Evolved: A high rate of SSH connections causes a Denial of Service","id":"CVE-2024-39562","kev_date_added":null,"published":"2024-07-10"},{"cvss_score":8.5,"headline":"Junos OS Evolved: Local, authenticated attacker can gain privileged access to FPCs","id":"CVE-2026-33788","kev_date_added":null,"published":"2026-04-09"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-09-16","vendors":["Juniper Networks"]},"summary":"An attacker can cause a sustained Denial of Service by sending specific Layer 2 frames that crash the packet forwarding engine in Junos OS Evolved.","url":"https://insights.sbomify.com/CVE-2021-0239/"}