{"id":"CVE-2026-98800","title":"bpf: Wait for an RCU tasks grace period before freeing trampoline progs","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Wait for an RCU tasks grace period before freeing trampoline progs\n\nWhen a prog is detached from a trampoline, it is freed after an RCU\ngrace period, or an RCU tas…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= e21aa341785c679dd409c8cb71f864c00fe6c463 < 40955f6512a03f0e046f5256b0706b26ba191018","Linux >= e21aa341785c679dd409c8cb71f864c00fe6c463 < 0fb5751a6e411b1b466c06e50021818d9391df98","Linux e21d2b92354b3cd25dd774ebb0f0e52ff04a7861","Linux 85d177f56e5256e14b74a65940f981f6e3e8bb32","Linux >= 5.10.28 < 5.11","Linux >= 5.11.11 < 5.12","Linux 5.12"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:48:46.223Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98800","references":[{"url":"https://git.kernel.org/stable/c/40955f6512a03f0e046f5256b0706b26ba191018"},{"url":"https://git.kernel.org/stable/c/0fb5751a6e411b1b466c06e50021818d9391df98"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.482Z","slug":"CVE-2026-98800","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Wait for an RCU tasks grace period before freeing trampoline progs\n\nWhen a prog is detached from a trampoline, it is freed after an RCU\ngrace period, or an RCU tasks trace one if it is sleepable. This covers\nthe tasks that are running the prog, since the prog's enter helper takes\nthe matching read lock before the prog is called. On a preemptible\nkernel, it doesn't cover a task that was preempted in the trampoline\njust before the enter helper. That task holds no lock yet, and it calls\nthe prog after it was freed:\n\n  BUG: KASAN: vmalloc-out-of-bounds in __bpf_prog_enter_recur+0x3a5/0x3f0\n  Read of size 8 at addr ffffc90000055040 by task candidate/110\n  CPU: 1 UID: 0 PID: 110 Comm: candidate Not tainted 7.3.0-rc2-00014-g15071f2a1263-dirty #2 PREEMPT(full)\n  Call Trace:\n   <TASK>\n   __bpf_prog_enter_recur+0x3a5/0x3f0\n   bpf_trampoline_6442509193+0x37/0xf1\n   __x64_sys_futex+0x9/0x410\n   do_syscall_64+0xb0/0x530\n   ...\n\nWait for an RCU tasks grace period before the existing one when freeing\na prog that was linked to a trampoline. An RCU tasks grace period only\nends once the tasks that were preempted have run again, and\nbpf_tramp_image_put() already relies on it to free the image. It doesn't\nwait for tasks that sleep in the trampoline, the next commit takes care\nof those.\n\nOnly progs that were linked to a trampoline can be called this way, so\nbpf_trampoline_add_prog() marks them and other progs are still freed as\nbefore.\n\n## Affected\n\n- `Linux >= e21aa341785c679dd409c8cb71f864c00fe6c463 < 40955f6512a03f0e046f5256b0706b26ba191018`\n- `Linux >= e21aa341785c679dd409c8cb71f864c00fe6c463 < 0fb5751a6e411b1b466c06e50021818d9391df98`\n- `Linux e21d2b92354b3cd25dd774ebb0f0e52ff04a7861`\n- `Linux 85d177f56e5256e14b74a65940f981f6e3e8bb32`\n- `Linux >= 5.10.28 < 5.11`\n- `Linux >= 5.11.11 < 5.12`\n- `Linux 5.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}