{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98230", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.328Z", "datePublished": "2026-10-06T08:45:04.548Z", "dateUpdated": "2026-10-19T09:16:02.121Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:16:02.121Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: use hlist_del_init_rcu for state_cache and state_cache_input\n\nCommit 14acf9652e56 (\"xfrm: defensively unhash xfrm_state lists in\n__xfrm_state_delete\") converted bydst/bysrc/byseq/byspi from\nhlist_del_rcu() to hlist_del_init_rcu() so that a second\n__xfrm_state_delete() on the same object becomes a no-op rather than a\nwrite through LIST_POISON pprev. It missed state_cache and\nstate_cache_input, which kept hlist_del_rcu():\n\n- hlist_del_rcu() leaves pprev = LIST_POISON2 (non-NULL), so\n hlist_unhashed() returns false.\n- hlist_del_init_rcu() leaves pprev = NULL, so hlist_unhashed()\n returns true.\n\nA second __xfrm_state_delete() therefore enters __hlist_del() on the\nalready-deleted state_cache/state_cache_input nodes and does\nWRITE_ONCE(*pprev, next) through LIST_POISON2 — a write use-after-free\nonce the slab is reused. The corruption can in turn cause a subsequent\nhlist_for_each_entry_rcu traversal to follow a dangling next pointer,\nproducing the read use-after-free reported in xfrm_input_state_lookup().\n\nSwitch state_cache and state_cache_input to hlist_del_init_rcu() to\nmatch the other four lists, closing the write use-after-free and, with\nit, the read use-after-free it spawns." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bad unlink is in __xfrm_state_delete(), reached when SAs are removed via XFRM_MSG_DELSA/FLUSHSA/EXPIRE over NETLINK_XFRM or the af_key socket, or via xfrm_timer_handler expiry. ESP packets only walk state_cache_input in xfrm_input_state_lookup() and carry no malformed data that causes the double unlink, so the vector is local.\nAC:H - A second unlink needs __xfrm_state_delete() to see a non-DEAD state that was already removed, but every caller holds x->lock and checks km.state. The only path found that skips the VALID check is mlx5e_ipsec_handle_event(), which calls xfrm_state_check_expire() on a hardware hard-limit event and needs mlx5 packet offload, so the attacker cannot reliably arrange it.\nPR:L - Adding, expiring and flushing SAs over NETLINK_XFRM needs CAP_NET_ADMIN only in the user namespace that owns the netns. An unprivileged user gets it with unshare -Urn, and each netns has its own state_cache_input percpu lists and xfrm_state_lock.\nUI:N - The attacker drives the SA lifecycle (add, expire, delete, flush) and the traffic that fills the state caches themselves. No other user has to do anything.\nS:U - The corrupted hlist nodes are inside struct xfrm_state in kernel slab memory, so the impact stays within the kernel's own security authority.\nC:H - After the stale-pprev unlink, the state_cache_input chain can keep a freed xfrm_state, which hlist_for_each_entry_rcu in xfrm_input_state_lookup() then dereferences (the read UAF the commit reports). With slab reuse, an attacker can control the contents of that object.\nI:H - __hlist_del() on an already-unlinked state_cache/state_cache_input node does WRITE_ONCE(*pprev, next) through a stale pointer, a write use-after-free into reused slab memory that corrupts RCU hash-chain linkage.\nA:H - Writing through LIST_POISON2, or walking the corrupted per-CPU state_cache_input or policy state_cache_list chain, causes a general protection fault or KASAN oops in softirq or netns cleanup context, which takes down the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_state.c" ], "versions": [ { "version": "aa48a18fdb0911572d133057cd579db704b87da4", "lessThan": "fb38fb7420d5f7192f9e2b6ac835ede149cd7ac5", "status": "affected", "versionType": "git" }, { "version": "0045e3d80613cc7174dc15f189ee6fc4e73b9365", "lessThan": "4748c27e2e6a1969e02f1df46e62f79d2799b80b", "status": "affected", "versionType": "git" }, { "version": "0045e3d80613cc7174dc15f189ee6fc4e73b9365", "lessThan": "9b74a47a4cbd0d29faff4f3b199212c73e6b6220", "status": "affected", "versionType": "git" }, { "version": "0045e3d80613cc7174dc15f189ee6fc4e73b9365", "lessThan": "2afb8dc1f4390f164db8352f8e685e126e9db566", "status": "affected", "versionType": "git" }, { "version": "5e4334dc39443645415450163ff5ff1ee7e79784", "status": "affected", "versionType": "git" }, { "version": "6.12.13", "lessThan": "6.12.112", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_state.c" ], "versions": [ { "version": "6.13", "status": "affected" }, { "version": "0", "lessThan": "6.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.54", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.8", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.13", "versionEndExcluding": "6.12.112" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "7.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fb38fb7420d5f7192f9e2b6ac835ede149cd7ac5" }, { "url": "https://git.kernel.org/stable/c/4748c27e2e6a1969e02f1df46e62f79d2799b80b" }, { "url": "https://git.kernel.org/stable/c/9b74a47a4cbd0d29faff4f3b199212c73e6b6220" }, { "url": "https://git.kernel.org/stable/c/2afb8dc1f4390f164db8352f8e685e126e9db566" } ], "title": "xfrm: use hlist_del_init_rcu for state_cache and state_cache_input", "x_generator": { "engine": "bippy-1.2.0" } } } }