{"id":"DEBIAN-CVE-2026-97937","details":"In the Linux kernel, the following vulnerability has been resolved:  ftrace: fork: Initialize function graph state before copy_exec_state()  dup_task_struct() copies the parent's task_struct, including ret_stack. ftrace_graph_init_task() clears the copied function graph state, but it currently runs after copy_exec_state().  For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, copy_process() reaches bad_fork_free and free_task() calls ftrace_graph_exit_task(). Since the child still carries the parent's ret_stack pointer, the unwind frees the parent's active function graph return stack. The parent subsequently accesses freed memory from function_graph_enter_regs().  KASAN reports:  [   22.190920] ================================================================== [   22.195899] BUG: KASAN: slab-use-after-free in function_graph_enter_regs+0xa76/0xb90 [   22.200747] Write of size 8 at addr ff110000054dc0a8 by task repro/1 [   22.205134] [   22.210770] CPU: 0 UID: 0 PID: 1 Comm: repro Not tainted 7.2.0-07732-g9328b3b03bdc-dirty #3 PREEMPT(lazy) [   22.212576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [   22.213750] Call Trace: [   22.215271]  \u003cTASK\u003e [   22.216242]  ? ftrace_stub_direct_tramp+0x10/0x10 [   22.217774]  dump_stack_lvl+0x4e/0x70 [   22.220531]  print_report+0x157/0x4b4 [   22.223202]  ? fixup_red_left+0x9/0x30 [   22.224407]  ? complete_report_info+0x83/0x110 [   22.226679]  ? function_graph_enter_regs+0xa76/0xb90 [   22.228084]  kasan_report+0xce/0x100 [   22.230109]  ? function_graph_enter_regs+0xa76/0xb90 [   22.232860]  ? stack_trace_save+0x4/0xd0 [   22.234156]  function_graph_enter_regs+0xa76/0xb90 [   22.236090]  ? kasan_save_stack+0x30/0x50 [   22.237752]  ? __pfx_function_graph_enter_regs+0x10/0x10 [   22.238694]  ? ring_buffer_lock_reserve+0x345/0xf80 [   22.239628]  ? stack_trace_save+0x4/0xd0 [   22.242121]  ? stack_trace_save+0x4/0xd0 [   22.243588]  ftrace_graph_func+0xda/0x160 [   22.245362]  ? ftrace_stub_direct_tramp+0x10/0x10 [   22.246520]  0xffffffffa0000095 [   22.250528]  ? stack_trace_save+0x9/0xd0 [   22.251757]  ? ring_buffer_unlock_commit+0x11d/0x5c0 [   22.253152]  stack_trace_save+0x9/0xd0 [   22.254264]  kasan_save_stack+0x30/0x50 [   22.273631]  kasan_save_track+0x14/0x30 [   22.276763]  kasan_save_free_info+0x3b/0x70 [   22.278296]  __kasan_slab_free+0x43/0x70 [   22.280157]  kmem_cache_free+0xbf/0x3b0 [   22.282963]  ? ftrace_stub_direct_tramp+0x10/0x10 [   22.284001]  free_task+0xa2/0x160 [   22.285699]  ? ftrace_stub_direct_tramp+0x10/0x10 [   22.286752]  copy_process+0x2aae/0x7bc0  Initialize the child function graph state immediately after dup_task_struct(), before the first fallible operation.","modified":"2026-09-26T05:01:07.399083391Z","published":"2026-09-25T11:17:21.080Z","upstream":["CVE-2026-97937"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-97937"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.12.100-1","6.12.101-1","6.12.105-1","6.12.107-1","6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1","6.12.94-1~bpo12+1","6.12.95-1","6.12.95-1~bpo12+1","6.12.96-1","6.13.10-1~exp1","6.13.11-1~exp1","6.13.2-1~exp1","6.13.3-1~exp1","6.13.4-1~exp1","6.13.5-1~exp1","6.13.6-1~exp1","6.13.7-1~exp1","6.13.8-1~exp1","6.13.9-1~exp1","6.13~rc6-1~exp1","6.13~rc7-1~exp1","6.14.3-1~exp1","6.14.5-1~exp1","6.14.6-1~exp1","6.15-1~exp1","6.15.1-1~exp1","6.15.2-1~exp1","6.15.3-1~exp1","6.15.4-1~exp1","6.15.5-1~exp1","6.15.6-1~exp1","6.15~rc7-1~exp1","6.16-1~exp1","6.16.1-1~exp1","6.16.10-1","6.16.11-1","6.16.12-1","6.16.12-1~bpo13+1","6.16.12-2","6.16.3-1","6.16.3-1~bpo13+1","6.16.5-1","6.16.6-1","6.16.7-1","6.16.8-1","6.16.9-1","6.16~rc7-1~exp1","6.17.10-1","6.17.11-1","6.17.12-1","6.17.13-1","6.17.13-1~bpo13+1","6.17.2-1~exp1","6.17.5-1~exp1","6.17.6-1","6.17.7-1","6.17.7-2","6.17.8-1","6.17.8-1~bpo13+1","6.17.9-1","6.18.1-1~exp1","6.18.10-1","6.18.12-1","6.18.12-1~bpo13+1","6.18.13-1","6.18.14-1","6.18.15-1","6.18.15-1~bpo13+1","6.18.2-1~exp1","6.18.3-1","6.18.5-1","6.18.5-1~bpo13+1","6.18.8-1","6.18.9-1","6.18.9-1~bpo13+1","6.18~rc4-1~exp1","6.18~rc4-1~exp2","6.18~rc5-1~exp1","6.18~rc6-1~exp1","6.18~rc7-1~exp1","6.19-1~exp1","6.19.10-1","6.19.10-1~bpo13+1","6.19.11-1","6.19.11-1~bpo13+1","6.19.12-1","6.19.13-1","6.19.13-1~bpo13+1","6.19.14-1","6.19.14-1~bpo13+1","6.19.2-1~exp1","6.19.3-1~exp1","6.19.4-1~exp1","6.19.5-1~exp1","6.19.6-1","6.19.6-2","6.19.6-2~bpo13+1","6.19.8-1","6.19.8-1~bpo13+1","6.19~rc4-1~exp1","6.19~rc5-1~exp1","6.19~rc6-1~exp1","6.19~rc7-1~exp1","6.19~rc8-1~exp1","7.0-1~exp1","7.0.1-1~exp1","7.0.10-1","7.0.10-1~bpo13+1","7.0.12-1","7.0.12-2","7.0.12-2~bpo13+1","7.0.13-1","7.0.13-1~bpo13+1","7.0.14-1","7.0.3-1","7.0.4-1","7.0.4-1~bpo13+1","7.0.7-1","7.0.7-1~bpo13+1","7.0.9-1","7.0.9-1~bpo13+1","7.1.1-1~exp1","7.1.10-1","7.1.12-1","7.1.13-1","7.1.2-1~exp1","7.1.3-1","7.1.3-1+sunvdc","7.1.3-1~bpo13+1","7.1.4-1","7.1.5-1","7.1.6-1","7.1.7-1","7.1.7-1~bpo13+1","7.1.8-1","7.1.8-1~bpo13+1","7.1.8-2","7.1.9-1","7.1.9-1+sparc64","7.1~rc2-1~exp1","7.1~rc3-1~exp1","7.1~rc4-1~exp1","7.1~rc4-1~exp2","7.1~rc5-1~exp1","7.1~rc7-1~exp1","7.2.2-1~exp1","7.2.3-1~exp1","7.2.6-1","7.2.7-1","7.2~rc3-1~exp1","7.2~rc5-1~exp1","7.2~rc7-1~exp1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-97937.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}