{"answers":{"affected":"It affects 2 products.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21901 exists.","fix":"No fix has been published for CVE-2026-21901 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-21901 is a medium-severity vulnerability in Juniper Junos, published on 9 Jul 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-2026-21901 and fix it if it is affected.\n\nWhat it is: CVE-2026-21901 is a medium-severity vulnerability in Juniper Junos, published on 9 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21901 exists.\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-2026-21901/ (Markdown: https://insights.sbomify.com/CVE-2026-21901/index.md)","id":"CVE-2026-21901","markdown":"https://insights.sbomify.com/CVE-2026-21901/index.md","name":"CVE-2026-21901","record":{"aliases":[],"analysis":{"component_type":"network_device","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Juniper Junos OS","requires_auth":"high_privilege","summary":"A local high-privileged attacker can cause a denial of service by triggering a null pointer dereference in the management daemon via specific SSH configuration changes.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"juniper","cpe":[{"product":"junos","vendor":"juniper"},{"product":"junos_os_evolved","vendor":"juniper"}],"cvss":{"score":6.7,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/AU:Y/R:A/V:D/RE:M/U:Green","version":"4.0"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"A NULL Pointer Dereference vulnerability in the management daemon (mgd) of Juniper Networks Junos OS and Junos OS Evolved allows a local, high-privileged attacker setting or deactivating a specific SSH configuration parameter to create a Denial of Service (DoS).\n\nA local high-privileged user configuring or deactivating a specific 'system services ssh' configuration parameter can exploit a null pointer dereference in one of the functions used by SSH. The function attempts to dereference a null pointer when accessing certain configuration data, resulting in an mgd process crash and restart. Continued execution of these configuration commands will create a sustained Denial of Service (DoS) condition.\n\nThis issue affects:\nJunos OS:\n\n  *  from 22.3 before 22.3R3-S5;\n  *  from 22.4 before 22.4R3-S10;\n  *  from 23.2 before 23.2R2-S7;\n  *  from 23.4 before 23.4R2-S8.\n\nThis issue does not affect Junos OS before 22.3R1.\n\nJunos OS Evolved:\n  *  from 22.3R1-EVO before 23.2R2-S7-EVO;\n  *  from 23.4 before 23.4R2-S8-EVO.\n\nThis issue does not affect Junos OS Evolved before 22.3R1-EVO.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":null,"headline":"Junos OS and Junos OS Evolved: Configuration of a specific SSH option results in mgd crash","id":"CVE-2026-21901","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"juniper:junos","products":["juniper:junos","juniper:junos_os_evolved"],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root","id":"CVE-2026-21902"},"packages":[],"prev":{"headline":"CryptoLib Has Out-of-Bounds Read in KMC Encrypt Metadata Parsing via Flawed strtok Pattern","id":"CVE-2026-21900"},"products":["Junos OS","Junos OS Evolved"],"published":"2026-07-09","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":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-10","vendors":["Juniper Networks"]},"summary":"A local high-privileged attacker can cause a denial of service by triggering a null pointer dereference in the management daemon via specific SSH configuration changes.","url":"https://insights.sbomify.com/CVE-2026-21901/"}