procfs: fix missing RCU protection when reading real_parent in do_task_stat()

Summary

In the Linux kernel, the following vulnerability has been resolved: procfs: fix missing RCU protection when reading real_parent in do_task_stat() When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent without proper RCU protection, which leads to: cpu 0 cpu 1 ----- ----- do_task_stat var = task->real_parent release_task call_rcu(delayed_put_task_struct) task_tgid_nr_ns(var) rcu_read_lock <--- Too late to protect task->real_parent! task_pid_ptr <--- UAF! rcu_read_unlock This patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add proper RCU protection for accessing task->real_parent.

Timeline

1. Jun 3, 2026, 3:49 PM UTCCVE published
2. Oct 16, 2026, 3:21 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 19, 2026, 7:36 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in fefa0fcd78be465b7ad4c497fa6ec90d64194c04; From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in c93a33f28f915d446eea6fb3f0e1def0b3af1982; From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in 1c8dc5b5517546c68ffae40b948336122bb61306; From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in 0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e; From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in 73ec7c96601d61d52310c659145bb06d933a0fa6; From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in 4f9ae386861e280b7631ca252f798d25575627ee; From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in dd8b13cb4ff1a4545a214ed897fdf2bc341155b6; From 06fffb1267c9d986687b69d74a46ee332a50575e · fixed in 76149d53502cf17ef3ae454ff384551236fba867

• Linux Linux

  2.6.26

• KernelLinux

  From 2.6.26 · fixed in 5.10.252; From 5.11.0 · fixed in 5.15.202; From 5.16.0 · fixed in 6.1.165; From 6.2.0 · fixed in 6.6.128; From 6.7.0 · fixed in 6.12.75; From 6.13.0 · fixed in 6.18.14; From 6.19.0 · fixed in 6.19.4

References 8