{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-40256 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40256 is a memory corruption vulnerability in Linux, published on 4 Dec 2025. 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-2025-40256 and fix it if it is affected.\n\nWhat it is: CVE-2025-40256 is a memory corruption vulnerability in Linux, published on 4 Dec 2025. 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-2025-40256 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-2025-40256/ (Markdown: https://insights.sbomify.com/CVE-2025-40256/index.md)","id":"CVE-2025-40256","markdown":"https://insights.sbomify.com/CVE-2025-40256/index.md","name":"CVE-2025-40256","record":{"aliases":["BELL-CVE-2025-40256","DEBIAN-CVE-2025-40256","GHSA-wxqp-f8fg-rxmv","UBUNTU-CVE-2025-40256"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A memory leak in the Linux kernel's xfrm subsystem allows local attackers to cause denial of service by triggering specific IPcomp tunnel state failures.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added\n\nIn commit b441cf3f8c4b (\"xfrm: delete x-\u003etunnel as we delete x\"), I\nmissed the case where state creation fails between full\ninitialization (-\u003einit_state has been called) and being inserted on\nthe lists.\n\nIn this situation, -\u003einit_state has been called, so for IPcomp\ntunnels, the fallback tunnel has been created and added onto the\nlists, but the user state never gets added, because we fail before\nthat. The user state doesn't go through __xfrm_state_delete, so we\ndon't call xfrm_state_delete_tunnel for those states, and we end up\nleaking the FB tunnel.\n\nThere are several codepaths affected by this: the add/update paths, in\nboth net/key and xfrm, and the migrate code (xfrm_migrate,\nxfrm_state_migrate). A \"proper\" rollback of the init_state work would\nprobably be doable in the add/update code, but for migrate it gets\nmore complicated as multiple states may be involved.\n\nAt some point, the new (not-inserted) state will be destroyed, so call\nxfrm_state_delete_tunnel during xfrm_state_gc_destroy. Most states\nwill have their fallback tunnel cleaned up during __xfrm_state_delete,\nwhich solves the issue that b441cf3f8c4b (and other patches before it)\naimed at. All states (including FB tunnels) will be removed from the\nlists once xfrm_state_fini has called flush_work(\u0026xfrm_state_gc_work).","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":"xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added","id":"CVE-2025-40256","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"memory_corruption","year":"2025"},"n_packages":0,"n_references":7,"next":{"headline":"mptcp: fix a race in mptcp_pm_del_add_timer()","id":"CVE-2025-40257"},"packages":[],"prev":{"headline":"net: core: prevent NULL deref in generic_hwtstamp_ioctl_lower()","id":"CVE-2025-40255"},"products":["Linux"],"published":"2025-12-04","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A memory leak in the Linux kernel's xfrm subsystem allows local attackers to cause denial of service by triggering specific IPcomp tunnel state failures.","url":"https://insights.sbomify.com/CVE-2025-40256/"}