{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-0263 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-0263 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-0263 is a medium-severity denial of service vulnerability in Juniper Junos, published on 22 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-0263 and fix it if it is affected.\n\nWhat it is: CVE-2021-0263 is a medium-severity denial of service vulnerability in Juniper Junos, published on 22 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-0263 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-2021-0263/ (Markdown: https://insights.sbomify.com/CVE-2021-0263/index.md)","id":"CVE-2021-0263","markdown":"https://insights.sbomify.com/CVE-2021-0263/index.md","name":"CVE-2021-0263","record":{"aliases":["GHSA-qcxv-8437-j2fr"],"analysis":{"component_type":"network_device","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"Juniper PTX router","requires_auth":"none","summary":"An attacker can cause a denial of service on Juniper PTX routers by triggering heavy route churn while J-Flow sampling is enabled.","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":5.9,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-19","name":null}],"description":"A Data Processing vulnerability in the Multi-Service process (multi-svcs) on the FPC of Juniper Networks Junos OS on the PTX Series routers may lead to the process becoming unresponsive, ultimately affecting traffic forwarding, allowing an attacker to cause a Denial of Service (DoS) condition . The Multi-Service Process running on the FPC is responsible for handling sampling-related operations when a J-Flow configuration is activated. This can occur during periods of heavy route churn, causing the Multi-Service Process to stop processing updates, without consuming any further updates from kernel. This back pressure towards the kernel affects further dynamic updates from other processes in the system, including RPD, causing a KRT-STUCK condition and traffic forwarding issues. An administrator can monitor the following command to check if there is the KRT queue is stuck: user@device \u003e show krt state ... Number of async queue entries: 65007 \u003c--- this value keep on increasing. The following logs/alarms will be observed when this condition exists: user@junos\u003e show chassis alarms 2 alarms currently active Alarm time Class Description 2020-10-11 04:33:45 PDT Minor Potential slow peers are: MSP(FPC1-PIC0) MSP(FPC3-PIC0) MSP(FPC4-PIC0) Logs: Oct 11 04:33:44.672 2020 test /kernel: rts_peer_cp_recv_timeout : Bit set for msp8 as it is stuck Oct 11 04:35:56.000 2020 test-lab fpc4 user.err gldfpc-multi-svcs.elf: Error in parsing composite nexthop Oct 11 04:35:56.000 2020 test-lab fpc4 user.err gldfpc-multi-svcs.elf: composite nexthop parsing error Oct 11 04:43:05 2020 test /kernel: rt_pfe_veto: Possible slowest client is msp38. States processed - 65865741. States to be processed - 0 Oct 11 04:55:55 2020 test /kernel: rt_pfe_veto: Memory usage of M_RTNEXTHOP type = (0) Max size possible for M_RTNEXTHOP type = (8311787520) Current delayed unref = (60000), Current unique delayed unref = (10896), Max delayed unref on this platform = (40000) Current delayed weight unref = (71426) Max delayed weight unref on this platform= (400000) curproc = rpd Oct 11 04:56:00 2020 test /kernel: rt_pfe_veto: Too many delayed route/nexthop unrefs. Op 2 err 55, rtsm_id 5:-1, msg type 2 This issue only affects PTX Series devices. No other products or platforms are affected by this vulnerability. This issue affects Juniper Networks Junos OS on PTX Series: 18.2 versions prior to 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R2-S8, 18.4R3-S7; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R3-S1; 19.3 versions prior to 19.3R3-S1; 19.4 versions prior to 19.4R2-S4, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2; 20.3 versions prior to 20.3R1-S2, 20.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 18.2R1.","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: PTX Series: Denial of Service in packet processing due to heavy route churn when J-Flow sampling is enabled","id":"CVE-2021-0263","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"juniper:junos","products":["juniper:junos"],"type":"denial_of_service","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"Denial of service in Junos OS","id":"CVE-2021-0264"},"packages":[],"prev":{"headline":"Junos OS: QFX10002-60C: Use after free vulnerability found during static code analysis","id":"CVE-2021-0262"},"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":"An attacker can cause a denial of service on Juniper PTX routers by triggering heavy route churn while J-Flow sampling is enabled.","url":"https://insights.sbomify.com/CVE-2021-0263/"}