{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-63828 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-63828 is a high-severity vulnerability in Linux, published on 19 Jul 2026. 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-2026-63828 and fix it if it is affected.\n\nWhat it is: CVE-2026-63828 is a high-severity vulnerability in Linux, published on 19 Jul 2026. 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-2026-63828 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-2026-63828/ (Markdown: https://insights.sbomify.com/CVE-2026-63828/index.md)","id":"CVE-2026-63828","markdown":"https://insights.sbomify.com/CVE-2026-63828/index.md","name":"CVE-2026-63828","record":{"aliases":["BELL-CVE-2026-63828","DEBIAN-CVE-2026-63828","GHSA-fvhv-v8p3-vrwq","ROOT-OS-DEBIAN-11-CVE-2026-63828","ROOT-OS-UBUNTU-2204-CVE-2026-63828","UBUNTU-CVE-2026-63828"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"AppArmor fails to mediate implicit connections in TCP Fast Open, allowing confined processes to bypass network restrictions.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":8.4,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: mediate the implicit connect of TCP fast open sendmsg\n\nsendmsg()/sendto() with MSG_FASTOPEN is a combination of connect(2) and\nwrite(2): it opens the connection in the SYN. apparmor_socket_sendmsg()\nonly checks AA_MAY_SEND, so a profile that grants send but denies connect\nlets a confined task open an outbound TCP/MPTCP connection that connect(2)\nwould have refused, bypassing connect mediation.\n\nMediate the implicit connect when MSG_FASTOPEN is set and a destination\nis supplied. Add it to apparmor_socket_sendmsg() (not the shared\naa_sock_msg_perm() helper, which recvmsg also uses) and call aa_sk_perm()\ndirectly, mirroring the selinux and tomoyo fixes. sk_is_tcp() does not\ncover MPTCP fast open, so the SOCK_STREAM/IPPROTO_MPTCP arm is explicit.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":"2026-09-02","github_poc":1,"max_poc_stars":1,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-09-02T21:23:08Z","kind":"github_poc","ref":"https://github.com/4n4s4zi/tfo-connect-bypass","stars":1,"title":"Using TCP Fast Open to bypass syscall-based networking rules (CVE-2026-63828/CVE-2026-72243 PoC)"}],"tier":"poc_unverified"},"has_fix":true,"headline":"apparmor: mediate the implicit connect of TCP fast open sendmsg","id":"CVE-2026-63828","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"security_feature_bypass","year":"2026"},"n_packages":0,"n_references":8,"next":{"headline":"net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink","id":"CVE-2026-63829"},"packages":[],"prev":{"headline":"apparmor: fix use-after-free in rawdata dedup loop","id":"CVE-2026-63827"},"products":["Linux"],"published":"2026-07-19","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-08-17","vendors":["Linux"]},"summary":"AppArmor fails to mediate implicit connections in TCP Fast Open, allowing confined processes to bypass network restrictions.","url":"https://insights.sbomify.com/CVE-2026-63828/"}