{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-74743 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-74743 is a critical use after free vulnerability in Linux, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-74743 and fix it if it is affected.\n\nWhat it is: CVE-2026-74743 is a critical use after free vulnerability in Linux, published on 26 Aug 2026. 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-2026-74743 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-74743/ (Markdown: https://insights.sbomify.com/CVE-2026-74743/index.md)","id":"CVE-2026-74743","markdown":"https://insights.sbomify.com/CVE-2026-74743/index.md","name":"CVE-2026-74743","record":{"aliases":["AZL-97782","BELL-CVE-2026-74743","DEBIAN-CVE-2026-74743","GHSA-5qfp-9h7g-rcpm","UBUNTU-CVE-2026-74743"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel macvlan","requires_auth":"none","summary":"A Linux kernel macvlan bug causes use-after-free crashes when lower devices require extra headroom, leading to denial of service.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"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\nmacvlan: inherit needed_headroom and needed_tailroom from lowerdev\n\nmacvlan devices inherit hard_header_len from lowerdev during macvlan_init(),\nbut leave needed_headroom and needed_tailroom set to 0.\n\nWhen the underlying lowerdev requires extra headroom or tailroom for\nheaders/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx\nheadroom), upper layers calculating packet headroom and tailroom fail to\nreserve sufficient space.\n\nThis can result in reallocation overhead, skb headroom underflows, or KASAN\nslab-use-after-free crashes when dev_hard_header() / macvlan_hard_header()\nprepends header data or when lower devices append tailroom.\n\nFix this by:\n1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init().\n2. Propagating needed_headroom and needed_tailroom updates to attached macvlans\n   in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events.","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":"macvlan: inherit needed_headroom and needed_tailroom from lowerdev","id":"CVE-2026-74743","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":8,"next":{"headline":"ipvlan: inherit needed_headroom and needed_tailroom from phy_dev","id":"CVE-2026-74744"},"packages":[],"prev":{"headline":"veth: fix queue index used to wake the peer txq in veth_poll","id":"CVE-2026-74742"},"products":["Linux"],"published":"2026-08-26","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-16","vendors":["Linux"]},"summary":"A Linux kernel macvlan bug causes use-after-free crashes when lower devices require extra headroom, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2026-74743/"}