CVE-2026-98800
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:
Wait for an RCU tasks grace period before the existing one when freeing a prog that was linked to a trampoline.
Read full descriptionShow less
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.
Technical details traces, logs and code from the original report
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 ...
CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.15 %
- Percentile among all scored CVEs
- 4
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Raw JSON (NVD)
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{
"id": "CVE-2026-98800",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "e21aa341785c679dd409c8cb71f864c00fe6c463",
"lessThan": "40955f6512a03f0e046f5256b0706b26ba191018",
"versionType": "git"
},
{
"status": "affected",
"version": "e21aa341785c679dd409c8cb71f864c00fe6c463",
"lessThan": "0fb5751a6e411b1b466c06e50021818d9391df98",
"versionType": "git"
},
{
"status": "affected",
"version": "e21d2b92354b3cd25dd774ebb0f0e52ff04a7861",
"versionType": "git"
},
{
"status": "affected",
"version": "85d177f56e5256e14b74a65940f981f6e3e8bb32",
"versionType": "git"
},
{
"status": "affected",
"version": "5.10.28",
"lessThan": "5.11",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.11.11",
"lessThan": "5.12",
"versionType": "semver"
}
],
"programFiles": [
"include/linux/bpf.h",
"kernel/bpf/syscall.c",
"kernel/bpf/trampoline.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.12"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.12",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.2.10",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/linux/bpf.h",
"kernel/bpf/syscall.c",
"kernel/bpf/trampoline.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:34.030",
"references": [
{
"url": "https://git.kernel.org/stable/c/0fb5751a6e411b1b466c06e50021818d9391df98",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/40955f6512a03f0e046f5256b0706b26ba191018",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"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'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."
}
],
"lastModified": "2026-10-19T10:19:44.050",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}