FKIE_CVE-2026-98800

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-19 10:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Wait for an RCU tasks grace period before freeing trampoline progs When a prog is detached from a trampoline, it is freed after an RCU grace period, or an RCU tasks trace one if it is sleepable. This covers the tasks that are running the prog, since the prog's enter helper takes the matching read lock before the prog is called. On a preemptible kernel, it doesn't cover a task that was preempted in the trampoline just before the enter helper. That task holds no lock yet, and it calls the prog after it was freed: BUG: KASAN: vmalloc-out-of-bounds in __bpf_prog_enter_recur+0x3a5/0x3f0 Read of size 8 at addr ffffc90000055040 by task candidate/110 CPU: 1 UID: 0 PID: 110 Comm: candidate Not tainted 7.3.0-rc2-00014-g15071f2a1263-dirty #2 PREEMPT(full) Call Trace: <TASK> __bpf_prog_enter_recur+0x3a5/0x3f0 bpf_trampoline_6442509193+0x37/0xf1 __x64_sys_futex+0x9/0x410 do_syscall_64+0xb0/0x530 ... Wait for an RCU tasks grace period before the existing one when freeing a prog that was linked to a trampoline. An RCU tasks grace period only ends once the tasks that were preempted have run again, and bpf_tramp_image_put() already relies on it to free the image. It doesn't wait for tasks that sleep in the trampoline, the next commit takes care of those. Only progs that were linked to a trampoline can be called this way, so bpf_trampoline_add_prog() marks them and other progs are still freed as before.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0fb5751a6e411b1b466c06e50021818d9391df98
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/40955f6512a03f0e046f5256b0706b26ba191018
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf.h",
            "kernel/bpf/syscall.c",
            "kernel/bpf/trampoline.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "40955f6512a03f0e046f5256b0706b26ba191018",
              "status": "affected",
              "version": "e21aa341785c679dd409c8cb71f864c00fe6c463",
              "versionType": "git"
            },
            {
              "lessThan": "0fb5751a6e411b1b466c06e50021818d9391df98",
              "status": "affected",
              "version": "e21aa341785c679dd409c8cb71f864c00fe6c463",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e21d2b92354b3cd25dd774ebb0f0e52ff04a7861",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "85d177f56e5256e14b74a65940f981f6e3e8bb32",
              "versionType": "git"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.28",
              "versionType": "semver"
            },
            {
              "lessThan": "5.12",
              "status": "affected",
              "version": "5.11.11",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf.h",
            "kernel/bpf/syscall.c",
            "kernel/bpf/trampoline.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.12"
            },
            {
              "lessThan": "5.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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 tasks trace one if it is sleepable. This covers\nthe tasks that are running the prog, since the prog\u0027s enter helper takes\nthe matching read lock before the prog is called. On a preemptible\nkernel, it doesn\u0027t 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   \u003cTASK\u003e\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\u0027t\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."
    }
  ],
  "id": "CVE-2026-98800",
  "lastModified": "2026-10-19T10:19:44.050",
  "metrics": {},
  "published": "2026-10-18T16:17:34.030",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0fb5751a6e411b1b466c06e50021818d9391df98"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/40955f6512a03f0e046f5256b0706b26ba191018"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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