{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-21910 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-21910 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-21910 is a high-severity denial of service vulnerability in Juniper Junos, published on 15 Jan 2026. 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-2026-21910 and fix it if it is affected.\n\nWhat it is: CVE-2026-21910 is a high-severity denial of service vulnerability in Juniper Junos, published on 15 Jan 2026. 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-2026-21910 in the wild and no public exploit code.\n\nAffected product: Juniper Junos. 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-2026-21910/ (Markdown: https://insights.sbomify.com/CVE-2026-21910/index.md)","id":"CVE-2026-21910","markdown":"https://insights.sbomify.com/CVE-2026-21910/index.md","name":"CVE-2026-21910","record":{"aliases":["GHSA-fhh6-4pm2-6vqv"],"analysis":{"component_type":"network_device","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Juniper network switch","requires_auth":"none","summary":"An unauthenticated attacker can cause a denial of service by flapping interfaces in EVPN-VXLAN configurations on specific Juniper switches.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"juniper","cpe":[{"product":"junos","vendor":"juniper"}],"cvss":{"score":7.1,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:U/RE:M/U:Green","version":"4.0"},"cwes":[{"id":"CWE-754","name":"Improper Check for Unusual or Exceptional Conditions"}],"description":"An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on EX4k Series and QFX5k Series platforms allows an unauthenticated network-adjacent attacker flapping an interface to cause traffic between VXLAN Network Identifiers (VNIs) to drop, leading to a Denial of Service (DoS).\n\nOn all EX4k and QFX5k platforms, a link flap in an\n\nEVPN-VXLAN configuration Link Aggregation Group (LAG)\nresults in Inter-VNI traffic dropping when there are multiple load-balanced next-hop routes for the same destination.\n\nThis issue is only applicable to systems that support EVPN-VXLAN Virtual Port-Link Aggregation Groups (VPLAG), such as the QFX5110, QFX5120, QFX5200, EX4100, EX4300, EX4400, and EX4650.\n\nService can only be restored by restarting the affected FPC via the 'request chassis fpc restart slot \u003cslot-number\u003e' command.\n\nThis issue affects Junos OS \n\non EX4k and QFX5k Series: \n\n  *  all versions before 21.4R3-S12, \n  *  all versions of 22.2\n  *  from 22.4 before 22.4R3-S8, \n  *  from 23.2 before 23.2R2-S5, \n  *  from 23.4 before 23.4R2-S5, \n  *  from 24.2 before 24.2R2-S3,\n  *  from 24.4 before 24.4R2.","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: EX4k Series, QFX5k Series: In an EVPN-VXLAN configuration link flaps cause Inter-VNI traffic drop","id":"CVE-2026-21910","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"juniper:junos","products":["juniper:junos"],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Junos OS Evolved: Flapping management interface causes MAC learning on label-switched interfaces to stop","id":"CVE-2026-21911"},"packages":[],"prev":{"headline":"Junos OS and Junos OS Evolved: Receipt of specific IS-IS update packet causes memory leak leading to RPD crash","id":"CVE-2026-21909"},"products":["Junos OS"],"published":"2026-01-15","related":[{"cvss_score":9.8,"headline":"Juniper Junos OS EX Series and SRX Series PHP External Variable Modification","id":"CVE-2023-36845","kev_date_added":"2023-11-13","published":"2023-08-17"},{"cvss_score":8.8,"headline":"Juniper Junos OS Path Traversal","id":"CVE-2020-1631","kev_date_added":"2022-03-25","published":"2020-05-04"},{"cvss_score":6.7,"headline":"Juniper Junos OS Improper Isolation or Compartmentalization","id":"CVE-2025-21590","kev_date_added":"2025-03-13","published":"2025-03-12"},{"cvss_score":5.3,"headline":"Juniper Junos OS SRX Series Missing Authentication for Critical Function","id":"CVE-2023-36851","kev_date_added":"2023-11-13","published":"2023-09-26"},{"cvss_score":5.3,"headline":"Juniper Junos OS EX Series PHP External Variable Modification","id":"CVE-2023-36844","kev_date_added":"2023-11-13","published":"2023-08-17"},{"cvss_score":5.3,"headline":"Juniper Junos OS SRX Series Missing Authentication for Critical Function","id":"CVE-2023-36846","kev_date_added":"2023-11-13","published":"2023-08-17"},{"cvss_score":5.3,"headline":"Juniper Junos OS EX Series Missing Authentication for Critical Function","id":"CVE-2023-36847","kev_date_added":"2023-11-13","published":"2023-08-17"}],"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":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-01-15","vendors":["Juniper Networks"]},"summary":"An unauthenticated attacker can cause a denial of service by flapping interfaces in EVPN-VXLAN configurations on specific Juniper switches.","url":"https://insights.sbomify.com/CVE-2026-21910/"}