GHSA-V8P9-M6WC-2CV3
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_bpf: prevent unbounded recursion in offload rollback
Quan Sun reported 1 a stack overflow in cls_bpf_offload_cmd().
Reproducer on netdevsim: add a skip_sw cls_bpf filter, set the
bpf_tc_accept debugfs knob to 0, then tc filter replace. The replace
calls tc_setup_cb_replace() which fails. cls_bpf_offload_cmd() then
swaps prog/oldprog and recursively calls itself to roll back. But
bpf_tc_accept=0 makes the rollback fail too, which triggers yet another
rollback frame with the same arguments, and so on until the stack is
exhausted.
bpf_tc_accept is just a convenient knob for the reproducer. Any driver whose tc_setup_cb_replace() fails twice in a row can hit the same loop, so this is not a netdevsim-only issue.
Two ways to fix it:
1) Have the rollback call tc_setup_cb_add() on oldprog instead of re-entering cls_bpf_offload_cmd(). 2) Mark the rollback frame with a flag and skip a second-level rollback from inside it.
Go with (2). It is the smaller change and keeps the original behaviour: the rollback still goes through tc_setup_cb_replace(), so the driver gets one real chance to restore its state. If that attempt also fails, we just return the original error instead of recursing.
{
"affected": [],
"aliases": [
"CVE-2026-74382"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:22:40Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_bpf: prevent unbounded recursion in offload rollback\n\nQuan Sun reported [1] a stack overflow in cls_bpf_offload_cmd().\n\nReproducer on netdevsim: add a skip_sw cls_bpf filter, set the\nbpf_tc_accept debugfs knob to 0, then `tc filter replace`. The replace\ncalls tc_setup_cb_replace() which fails. cls_bpf_offload_cmd() then\nswaps prog/oldprog and recursively calls itself to roll back. But\nbpf_tc_accept=0 makes the rollback fail too, which triggers yet another\nrollback frame with the same arguments, and so on until the stack is\nexhausted.\n\nbpf_tc_accept is just a convenient knob for the reproducer. Any driver\nwhose tc_setup_cb_replace() fails twice in a row can hit the same loop,\nso this is not a netdevsim-only issue.\n\nTwo ways to fix it:\n\n 1) Have the rollback call tc_setup_cb_add() on oldprog instead of\n re-entering cls_bpf_offload_cmd().\n 2) Mark the rollback frame with a flag and skip a second-level\n rollback from inside it.\n\nGo with (2). It is the smaller change and keeps the original behaviour:\nthe rollback still goes through tc_setup_cb_replace(), so the driver\ngets one real chance to restore its state. If that attempt also fails,\nwe just return the original error instead of recursing.\n\n[1]: https://lore.kernel.org/bpf/ce5a6005-3c5e-4696-9e05-eba9461dc860@std.uestc.edu.cn/T/#u",
"id": "GHSA-v8p9-m6wc-2cv3",
"modified": "2026-08-15T06:32:32Z",
"published": "2026-08-15T06:32:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74382"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/10753da2d659dd425a6e620f47f86852d604f67f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1387f252a242a51bfbb6eace29c8f8db21b457da"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/27db54b90bcc7c37867fe664107fa25ea6a116e4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/33373e1f378a501bc51aa73312f74295c84e3101"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3fa6fb5d771c992ebedbfa7331c6bcc6f33f89b7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4a76953c3ed043797e81529b9395e9ca6f4c7609"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a018f208ab7512380bd4cf670064d48cba00a1b1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e2d3b7bab3748c811dc5750ce9a8d62bc7f90ed7"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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Nomenclature
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