{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-97937", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:18:58.204Z", "datePublished": "2026-09-25T10:22:51.075Z", "dateUpdated": "2026-10-19T09:11:03.903Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:11:03.903Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nftrace: fork: Initialize function graph state before copy_exec_state()\n\ndup_task_struct() copies the parent's task_struct, including ret_stack.\nftrace_graph_init_task() clears the copied function graph state, but it\ncurrently runs after copy_exec_state().\n\nFor non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state.\nIf that allocation fails, copy_process() reaches bad_fork_free and\nfree_task() calls ftrace_graph_exit_task(). Since the child still carries\nthe parent's ret_stack pointer, the unwind frees the parent's active\nfunction graph return stack. The parent subsequently accesses freed memory\nfrom function_graph_enter_regs().\n\nKASAN reports:\n\n[ 22.190920] ==================================================================\n[ 22.195899] BUG: KASAN: slab-use-after-free in function_graph_enter_regs+0xa76/0xb90\n[ 22.200747] Write of size 8 at addr ff110000054dc0a8 by task repro/1\n[ 22.205134]\n[ 22.210770] CPU: 0 UID: 0 PID: 1 Comm: repro Not tainted 7.2.0-07732-g9328b3b03bdc-dirty #3 PREEMPT(lazy)\n[ 22.212576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[ 22.213750] Call Trace:\n[ 22.215271] \n[ 22.216242] ? ftrace_stub_direct_tramp+0x10/0x10\n[ 22.217774] dump_stack_lvl+0x4e/0x70\n[ 22.220531] print_report+0x157/0x4b4\n[ 22.223202] ? fixup_red_left+0x9/0x30\n[ 22.224407] ? complete_report_info+0x83/0x110\n[ 22.226679] ? function_graph_enter_regs+0xa76/0xb90\n[ 22.228084] kasan_report+0xce/0x100\n[ 22.230109] ? function_graph_enter_regs+0xa76/0xb90\n[ 22.232860] ? stack_trace_save+0x4/0xd0\n[ 22.234156] function_graph_enter_regs+0xa76/0xb90\n[ 22.236090] ? kasan_save_stack+0x30/0x50\n[ 22.237752] ? __pfx_function_graph_enter_regs+0x10/0x10\n[ 22.238694] ? ring_buffer_lock_reserve+0x345/0xf80\n[ 22.239628] ? stack_trace_save+0x4/0xd0\n[ 22.242121] ? stack_trace_save+0x4/0xd0\n[ 22.243588] ftrace_graph_func+0xda/0x160\n[ 22.245362] ? ftrace_stub_direct_tramp+0x10/0x10\n[ 22.246520] 0xffffffffa0000095\n[ 22.250528] ? stack_trace_save+0x9/0xd0\n[ 22.251757] ? ring_buffer_unlock_commit+0x11d/0x5c0\n[ 22.253152] stack_trace_save+0x9/0xd0\n[ 22.254264] kasan_save_stack+0x30/0x50\n[ 22.273631] kasan_save_track+0x14/0x30\n[ 22.276763] kasan_save_free_info+0x3b/0x70\n[ 22.278296] __kasan_slab_free+0x43/0x70\n[ 22.280157] kmem_cache_free+0xbf/0x3b0\n[ 22.282963] ? ftrace_stub_direct_tramp+0x10/0x10\n[ 22.284001] free_task+0xa2/0x160\n[ 22.285699] ? ftrace_stub_direct_tramp+0x10/0x10\n[ 22.286752] copy_process+0x2aae/0x7bc0\n\nInitialize the child function graph state immediately after\ndup_task_struct(), before the first fallible operation." } ], "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 - Triggered by a local fork()/clone() without CLONE_VM entering copy_process(): copy_exec_state() -> task_exec_state_copy() fails, and bad_fork_free -> free_task() -> ftrace_graph_exit_task() frees the ret_stack pointer the child inherited from the parent. No remote input is involved.\nAC:L - placeholder\nPR:L - placeholder\nUI:N - placeholder\nS:U - placeholder\nC:H - placeholder\nI:H - placeholder\nA:H - placeholder" } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/fork.c" ], "versions": [ { "version": "6b1c66c9cca99bf00386481c7b2aa7394c26d8b8", "lessThan": "1fadebbbf31f65beba353fa9d1373bf183e03fed", "status": "affected", "versionType": "git" }, { "version": "6b1c66c9cca99bf00386481c7b2aa7394c26d8b8", "lessThan": "08cacffeef8f64f1a222c93467ca84f24a46c953", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/fork.c" ], "versions": [ { "version": "7.2", "status": "affected" }, { "version": "0", "lessThan": "7.2", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.7", "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": "7.2", "versionEndExcluding": "7.2.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/1fadebbbf31f65beba353fa9d1373bf183e03fed" }, { "url": "https://git.kernel.org/stable/c/08cacffeef8f64f1a222c93467ca84f24a46c953" } ], "title": "ftrace: fork: Initialize function graph state before copy_exec_state()", "x_generator": { "engine": "bippy-1.2.0" } } } }