{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-72404 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-72404 is a high-severity use after free vulnerability in Linux, published on 15 Aug 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-2026-72404 and fix it if it is affected.\n\nWhat it is: CVE-2026-72404 is a high-severity use after free vulnerability in Linux, published on 15 Aug 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-2026-72404 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-2026-72404/ (Markdown: https://insights.sbomify.com/CVE-2026-72404/index.md)","id":"CVE-2026-72404","markdown":"https://insights.sbomify.com/CVE-2026-72404/index.md","name":"CVE-2026-72404","record":{"aliases":["AZL-96387","BELL-CVE-2026-72404","DEBIAN-CVE-2026-72404","GHSA-xhxf-mw58-xfpx","UBUNTU-CVE-2026-72404"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service","code_execution"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel TIPC UDP bearer teardown allows attackers to cause crashes or potentially execute code via race conditions.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/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\ntipc: fix UAF in cleanup_bearer() due to premature dst_cache_destroy()\n\nTIPC UDP media bearer teardown calls dst_cache_destroy() on its\nreplicast caches before calling synchronize_net() to wait for\nconcurrent RCU readers (transmitters) to finish:\n\nstatic void cleanup_bearer(struct work_struct *work)\n{\n...\n\tlist_for_each_entry_safe(rcast, tmp, \u0026ub-\u003ercast.list, list) {\n\t\tdst_cache_destroy(\u0026rcast-\u003edst_cache);\n\t\tlist_del_rcu(\u0026rcast-\u003elist);\n\t\tkfree_rcu(rcast, rcu);\n\t}\n...\n\tdst_cache_destroy(\u0026ub-\u003ercast.dst_cache);\n\tudp_tunnel_sock_release(ub-\u003esk);\n\tsynchronize_net();\n...\n}\n\nThis is highly buggy because dst_cache_destroy() immediately frees the\nper-CPU cache memory (free_percpu()) and releases the cached dst\nentries without any synchronization.\n\nIf a concurrent transmitter (e.g., tipc_udp_xmit()) is running on another\nCPU under RCU protection, it can call dst_cache_get() concurrently,\nleading to:\n1. Use-After-Free on the per-CPU cache pointer itself (crash).\n2. \"rcuref - imbalanced put()\" warning if it attempts to release a\n   dst that was concurrently released by dst_cache_destroy().\n\nFurthermore, calling kfree(ub) immediately after synchronize_net() without\nclosing the socket first (or waiting after closing it) leaves a window\nwhere a concurrent receiver (tipc_udp_recv()) could start after\nsynchronize_net(), access ub, and suffer a UAF when kfree(ub) runs.\n\nTo fix this, we must defer dst_cache_destroy() and kfree(ub) until after\nwe have ensured that no more readers can see the bearer/socket and all\nexisting readers have finished:\n\n1. Defer rcast entry destruction (both dst_cache_destroy() and kfree())\n   to an RCU callback using call_rcu_hurry().\n   Using call_rcu_hurry() ensures the dst entries are released quickly.\n\n2. Release the bearer socket using udp_tunnel_sock_release() (stops\n   new receive readers).\n\n3. Call synchronize_net() to wait for all outstanding RCU readers\n   (both transmit and receive) to finish.\n\n4. Now that it is safe, call dst_cache_destroy() on the main bearer\n   cache, and free ub.\n\nNote: 3) and 4) can be changed later in net-next to also use\ncall_rcu_hurry() and get rid of the synchronize_net() latency.","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":"tipc: fix UAF in cleanup_bearer() due to premature dst_cache_destroy()","id":"CVE-2026-72404","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync","id":"CVE-2026-72405"},"packages":[],"prev":{"headline":"ALSA: FCP: Fix NULL pointer dereference in interface lookup","id":"CVE-2026-72403"},"products":["Linux"],"published":"2026-08-15","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":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-21","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel TIPC UDP bearer teardown allows attackers to cause crashes or potentially execute code via race conditions.","url":"https://insights.sbomify.com/CVE-2026-72404/"}