{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-3455 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-3455 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-3455 is a medium-severity use after free vulnerability in Zephyrproject Zephyr, published on 19 Oct 2021. 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-2021-3455 and fix it if it is affected.\n\nWhat it is: CVE-2021-3455 is a medium-severity use after free vulnerability in Zephyrproject Zephyr, published on 19 Oct 2021. 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-2021-3455 in the wild and no public exploit code.\n\nAffected product: Zephyrproject Zephyr. 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-2021-3455/ (Markdown: https://insights.sbomify.com/CVE-2021-3455/index.md)","id":"CVE-2021-3455","markdown":"https://insights.sbomify.com/CVE-2021-3455/index.md","name":"CVE-2021-3455","record":{"aliases":[],"analysis":{"component_type":"operating_system","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Zephyr RTOS","requires_auth":"none","summary":"An attacker can cause a system freeze by disconnecting an L2CAP channel immediately after sending an invalid ATT request in Zephyr RTOS.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"zephyr","cpe":[{"product":"zephyr","vendor":"zephyrproject"}],"cvss":{"score":4.3,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"Disconnecting L2CAP channel right after invalid ATT request leads freeze. Zephyr versions \u003e= 2.4.0, \u003e= 2.5.0 contain Use After Free (CWE-416). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-7g38-3x9v-v7vp","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":"Disconnecting L2CAP channel right after invalid ATT request leads freeze","id":"CVE-2021-3455","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"zephyrproject:zephyr","products":["zephyrproject:zephyr"],"type":"use_after_free","year":"2021"},"n_packages":0,"n_references":1,"next":{"headline":"Missing authorization in smart proxy salt","id":"CVE-2021-3456"},"packages":[],"prev":{"headline":"Truncated L2CAP K-frame causes assertion failure","id":"CVE-2021-3454"},"products":["zephyr"],"published":"2021-10-19","related":[{"cvss_score":9.8,"headline":"Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key","id":"CVE-2026-5067","kev_date_added":null,"published":"2026-06-09"},{"cvss_score":9.8,"headline":"Bluetooth HCI Error Handling Double Free","id":"CVE-2022-3806","kev_date_added":null,"published":"2023-01-19"},{"cvss_score":9.8,"headline":"Memory corruption in getaddrinfo","id":"CVE-2017-14199","kev_date_added":null,"published":"2019-04-12"},{"cvss_score":9.8,"headline":"Null dereference in n/a","id":"CVE-2018-1000800","kev_date_added":null,"published":"2018-09-06"},{"cvss_score":9.6,"headline":"DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer","id":"CVE-2021-3329","kev_date_added":null,"published":"2023-02-26"},{"cvss_score":9.6,"headline":"DoS: Invalid Initialization in le_read_buffer_size_complete","id":"CVE-2023-0397","kev_date_added":null,"published":"2023-01-19"},{"cvss_score":9.6,"headline":"Usb bluetooth device ACL read cb buffer overflow","id":"CVE-2021-3966","kev_date_added":null,"published":"2023-01-11"}],"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":["zephyrproject-rtos"]},"summary":"An attacker can cause a system freeze by disconnecting an L2CAP channel immediately after sending an invalid ATT request in Zephyr RTOS.","url":"https://insights.sbomify.com/CVE-2021-3455/"}