{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47036 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47036 is a critical denial of service vulnerability in Linux kernel, published on 28 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-47036 and fix it if it is affected.\n\nWhat it is: CVE-2021-47036 is a critical denial of service vulnerability in Linux kernel, published on 28 Feb 2024. 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-2021-47036 in the wild and no public exploit code.\n\nAffected product: Linux kernel. 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-2021-47036/ (Markdown: https://insights.sbomify.com/CVE-2021-47036/index.md)","id":"CVE-2021-47036","markdown":"https://insights.sbomify.com/CVE-2021-47036/index.md","name":"CVE-2021-47036","record":{"aliases":["DEBIAN-CVE-2021-47036","GHSA-h958-4cw7-rqgr","ROOT-OS-DEBIAN-11-CVE-2021-47036","UBUNTU-CVE-2021-47036"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"Linux kernel","requires_auth":"none","summary":"A Linux kernel flaw in UDP tunnel handling can cause inner protocol corruption and packet holding, leading to denial of service when specific GRO features are enabled.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":9.8,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nudp: skip L4 aggregation for UDP tunnel packets\n\nIf NETIF_F_GRO_FRAGLIST or NETIF_F_GRO_UDP_FWD are enabled, and there\nare UDP tunnels available in the system, udp_gro_receive() could end-up\ndoing L4 aggregation (either SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST) at\nthe outer UDP tunnel level for packets effectively carrying and UDP\ntunnel header.\n\nThat could cause inner protocol corruption. If e.g. the relevant\npackets carry a vxlan header, different vxlan ids will be ignored/\naggregated to the same GSO packet. Inner headers will be ignored, too,\nso that e.g. TCP over vxlan push packets will be held in the GRO\nengine till the next flush, etc.\n\nJust skip the SKB_GSO_UDP_L4 and SKB_GSO_FRAGLIST code path if the\ncurrent packet could land in a UDP tunnel, and let udp_gro_receive()\ndo GRO via udp_sk(sk)-\u003egro_receive.\n\nThe check implemented in this patch is broader than what is strictly\nneeded, as the existing UDP tunnel could be e.g. configured on top of\na different device: we could end-up skipping GRO at-all for some packets.\n\nAnyhow, that is a very thin corner case and covering it will add quite\na bit of complexity.\n\nv1 -\u003e v2:\n - hopefully clarify the commit message","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"udp: skip L4 aggregation for UDP tunnel packets","id":"CVE-2021-47036","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"ASoC: q6afe-clocks: fix reprobing of the driver","id":"CVE-2021-47037"},"packages":[],"prev":{"headline":"iommu/vt-d: Remove WO permissions on second-level paging entries","id":"CVE-2021-47035"},"products":["Linux"],"published":"2024-02-28","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"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":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A Linux kernel flaw in UDP tunnel handling can cause inner protocol corruption and packet holding, leading to denial of service when specific GRO features are enabled.","url":"https://insights.sbomify.com/CVE-2021-47036/"}