{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68415","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-30T09:28:09.391Z","datePublished":"2026-08-10T12:04:35.425Z","dateUpdated":"2026-08-17T05:05:09.173Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:05:09.173Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: clear mode callbacks after failed mode setup\n\nxfrm_state_gc_task can run long after a failed IPTFS state setup. In the\nreproduced case, __xfrm_init_state() cached x->mode_cbs, IPTFS setup\nreturned -ENOMEM before publishing mode_data, and the temporary module\nreference from xfrm_get_mode_cbs() was dropped immediately. The dead state\nthen kept x->mode_cbs until deferred GC ran after xfrm_iptfs had been\nunloaded.\n\nClear x->mode_cbs when mode init or clone fails before publishing\nmode_data. Those states never installed mode-specific state or the\nlong-term IPTFS module pin, so deferred GC has nothing mode-specific to\ndestroy and must not retain a callback table pointer past the temporary\nlookup reference.\n\nThe buggy scenario involves two paths, with each column showing the order\nwithin that path:\n\nfailed setup path:\n1. cache x->mode_cbs\n2. mode setup fails before mode_data\n3. drop the temporary module ref\n4. dead state keeps x->mode_cbs cached\n\nGC/unload path:\n1. xfrm_state_put() queues GC work\n2. xfrm_iptfs unloads later\n3. xfrm_state_gc_task runs\n4. GC dereferences stale x->mode_cbs\n\nThis also covers the failed clone path where clone_state() returns before\npublishing mode_data.\n\nValidation reproduced this kernel report:\nKernel panic - not syncing: Fatal exception\nCONFIG_FAULT_INJECTION_STACKTRACE_FILTER=y\nfailslab_stacktrace_filter matched xfrm_iptfs frames\nack_error=-12\nFAULT_INJECTION: forcing a failure\nBUG: unable to handle page fault\nWorkqueue: events xfrm_state_gc_task\nRIP: xfrm_state_gc_task+0x142/0x650\nModules linked in: esp4_offload xfrm_user [last unloaded: xfrm_iptfs]\nKernel panic - not syncing: Fatal exception"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable paths are reached only through the XFRM configuration interface — netlink XFRM_MSG_NEWSA/XFRM_MSG_MIGRATE handled by xfrm_user.c — which requires a local socket on the machine; no remote peer data reaches this code.\nAC:L - The attacker fully controls SA creation and the failing allocation size (XFRMA_IPTFS_REORDER_WINDOW up to 65535 slots, ~1MB order-8 kmalloc), so the -ENOMEM setup failure is attacker-inducible and repeatable, and unlimited poisoned dead states can be armed so the stale x->mode_cbs dereference in xfrm_state_gc_task is hit deterministically once xfrm_iptfs is unloaded.\nPR:L - xfrm_user_rcv_msg() gates on netlink_net_capable(skb, CAP_NET_ADMIN), which is evaluated against the net namespace's user_ns, so any unprivileged local user obtains it with `unshare -Urn`; the IPTFS module is auto-loaded on demand by xfrm_get_mode_cbs().\nUI:N - The attacker performs the entire sequence with netlink messages from its own process; no victim action, mount, or file open is needed to arm or trigger the dead state's deferred GC.\nS:U - The stale callback dereference occurs in kernel context within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - xfrm_state_gc_task loads x->mode_cbs->destroy_state from module memory that was freed by module unload and can be reoccupied by attacker-influenced allocations, giving a stale-pointer read/indirect-call primitive that can be leveraged to disclose arbitrary kernel memory.\nI:H - Calling a function pointer read out of freed module text/rodata is a control-flow hijack primitive; combined with the missing module reference that lets the memory be recycled, this permits arbitrary kernel-state modification rather than a benign fault.\nA:H - The commit's reproducer shows the direct outcome is \"BUG: unable to handle page fault\" in the events workqueue running xfrm_state_gc_task, escalating to \"Kernel panic - not syncing: Fatal exception\" — a full system crash."}]}],"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":"4b3faf610cc63bfac972711635eafbca5e7d7117","lessThan":"9845a35986a658816f7752f7ebd7c455a4c7dfdf","status":"affected","versionType":"git"},{"version":"4b3faf610cc63bfac972711635eafbca5e7d7117","lessThan":"c37a079230128a5237f45fb4e181bc069a5c2955","status":"affected","versionType":"git"},{"version":"4b3faf610cc63bfac972711635eafbca5e7d7117","lessThan":"2538bd3cd1ff5af655908469544ac7b7ae259386","status":"affected","versionType":"git"}]},{"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":"6.14","status":"affected"},{"version":"0","lessThan":"6.14","status":"unaffected","versionType":"semver"},{"version":"6.18.42","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.6","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","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":"6.14","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/9845a35986a658816f7752f7ebd7c455a4c7dfdf"},{"url":"https://git.kernel.org/stable/c/c37a079230128a5237f45fb4e181bc069a5c2955"},{"url":"https://git.kernel.org/stable/c/2538bd3cd1ff5af655908469544ac7b7ae259386"}],"title":"xfrm: clear mode callbacks after failed mode setup","x_generator":{"engine":"bippy-1.2.0"}}}}