{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-0247 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-0247 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-0247 is a medium-severity vulnerability in Juniper Junos, published on 22 Apr 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2021-0247 and fix it if it is affected.\n\nWhat it is: CVE-2021-0247 is a medium-severity vulnerability in Juniper Junos, published on 22 Apr 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2021-0247 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-2021-0247/ (Markdown: https://insights.sbomify.com/CVE-2021-0247/index.md)","id":"CVE-2021-0247","markdown":"https://insights.sbomify.com/CVE-2021-0247/index.md","name":"CVE-2021-0247","record":{"aliases":["GHSA-r8xp-mxfm-j25m"],"analysis":{"component_type":"network_device","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Juniper network switch","requires_auth":"high_privilege","summary":"A race condition in Junos OS allows attackers to bypass input loopback firewall filters, potentially exposing protected interfaces.","user_interaction":"required","vuln_class":"race_condition"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"juniper","cpe":[{"product":"junos","vendor":"juniper"}],"cvss":{"score":5.1,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:L","version":"3.1"},"cwes":[{"id":"CWE-362","name":"Concurrent Execution using Shared Resource with Improper Synchronization"}],"description":"A Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization) vulnerability in the firewall process (dfwd) of Juniper Networks Junos OS allows an attacker to bypass the firewall rule sets applied to the input loopback filter on any interfaces of a device. This issue is detectable by reviewing the PFE firewall rules, as well as the firewall counters and seeing if they are incrementing or not. For example: show firewall Filter: __default_bpdu_filter__ Filter: FILTER-INET-01 Counters: Name Bytes Packets output-match-inet 0 0 \u003c\u003c\u003c\u003c\u003c\u003c missing firewall packet count This issue affects: Juniper Networks Junos OS 14.1X53 versions prior to 14.1X53-D53 on QFX Series; 14.1 versions 14.1R1 and later versions prior to 15.1 versions prior to 15.1R7-S6 on QFX Series, PTX Series; 15.1X53 versions prior to 15.1X53-D593 on QFX Series; 16.1 versions prior to 16.1R7-S7 on QFX Series, PTX Series; 16.2 versions prior to 16.2R2-S11, 16.2R3 on QFX Series, PTX Series; 17.1 versions prior to 17.1R2-S11, 17.1R3-S2 on QFX Series, PTX Series; 17.2 versions prior to 17.2R1-S9, 17.2R3-S3 on QFX Series, PTX Series; 17.3 versions prior to 17.3R2-S5, 17.3R3-S7 on QFX Series, PTX Series; 17.4 versions prior to 17.4R2-S9, 17.4R3 on QFX Series, PTX Series; 18.1 versions prior to 18.1R3-S9 on QFX Series, PTX Series; 18.2 versions prior to 18.2R2-S6, 18.2R3-S3 on QFX Series, PTX Series; 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3-S1 on QFX Series, PTX Series; 18.4 versions prior to 18.4R1-S5, 18.4R2-S3, 18.4R2-S7, 18.4R3 on QFX Series, PTX Series; 19.1 versions prior to 19.1R1-S4, 19.1R2-S1, 19.1R3 on QFX Series, PTX Series; 19.2 versions prior to 19.2R1-S3, 19.2R2 on QFX Series, PTX Series.","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":"Race condition in Junos OS","id":"CVE-2021-0247","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"juniper:junos","products":["juniper:junos"],"type":"race_condition","year":"2021"},"n_packages":0,"n_references":1,"next":{"headline":"NFX Series: Hard-coded credentials allow an attacker to take control of any instance through administrative interfaces.","id":"CVE-2021-0248"},"packages":[],"prev":{"headline":"Missing authorization in Junos OS","id":"CVE-2021-0246"},"products":["Junos OS"],"published":"2021-04-22","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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-09-16","vendors":["Juniper Networks"]},"summary":"A race condition in Junos OS allows attackers to bypass input loopback firewall filters, potentially exposing protected interfaces.","url":"https://insights.sbomify.com/CVE-2021-0247/"}