{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-21903 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-21903 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-21903 is a high-severity memory corruption vulnerability in Juniper Junos, published on 15 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-21903 and fix it if it is affected.\n\nWhat it is: CVE-2026-21903 is a high-severity memory corruption vulnerability in Juniper Junos, published on 15 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-21903 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-2026-21903/ (Markdown: https://insights.sbomify.com/CVE-2026-21903/index.md)","id":"CVE-2026-21903","markdown":"https://insights.sbomify.com/CVE-2026-21903/index.md","name":"CVE-2026-21903","record":{"aliases":["GHSA-h3c8-3472-7v7g"],"analysis":{"component_type":"network_device","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Junos OS","requires_auth":"low_privilege","summary":"Authenticated low-privilege attackers can cause a denial of service by triggering a stack-based buffer overflow in the Packet Forwarding Engine via telemetry subscriptions.","user_interaction":"not_required","vuln_class":"memory_corruption"},"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:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L","version":"4.0"},"cwes":[{"id":"CWE-121","name":"Stack-based Buffer Overflow"}],"description":"A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated with low privileges to cause a Denial-of-Service (DoS).\n\nSubscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart.\nThe issue was not seen when YANG packages for the specific sensors were installed. \n\nThis issue affects Junos OS: \n\n  *  all versions before 22.4R3-S7,\n  *  23.2 version before 23.2R2-S4,\n  *  23.4 versions before 23.4R2.","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: Subscribing to telemetry sensors at scale causes all FPCs to crash","id":"CVE-2026-21903","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"juniper:junos","products":["juniper:junos"],"type":"memory_corruption","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Junos Space: ilpFilter field on nLegacy.jsp is vulnerable to reflected cross-site script injection","id":"CVE-2026-21904"},"packages":[],"prev":{"headline":"Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root","id":"CVE-2026-21902"},"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":"Authenticated low-privilege attackers can cause a denial of service by triggering a stack-based buffer overflow in the Packet Forwarding Engine via telemetry subscriptions.","url":"https://insights.sbomify.com/CVE-2026-21903/"}