---
id: CVE-2026-74382
title: 'net/sched: cls_bpf: prevent unbounded recursion in offload rollback'
summary: |-
  In 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 sk…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    a018f208ab7512380bd4cf670064d48cba00a1b1
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    33373e1f378a501bc51aa73312f74295c84e3101
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    e2d3b7bab3748c811dc5750ce9a8d62bc7f90ed7
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    4a76953c3ed043797e81529b9395e9ca6f4c7609
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    1387f252a242a51bfbb6eace29c8f8db21b457da
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    10753da2d659dd425a6e620f47f86852d604f67f
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    3fa6fb5d771c992ebedbfa7331c6bcc6f33f89b7
  - >-
    Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 <
    27db54b90bcc7c37867fe664107fa25ea6a116e4
  - Linux 4.15
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:56:47.875311Z'
published: '2026-08-15'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T17:05:45.139Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74382'
references:
  - url: 'https://git.kernel.org/stable/c/a018f208ab7512380bd4cf670064d48cba00a1b1'
  - url: 'https://git.kernel.org/stable/c/33373e1f378a501bc51aa73312f74295c84e3101'
  - url: 'https://git.kernel.org/stable/c/e2d3b7bab3748c811dc5750ce9a8d62bc7f90ed7'
  - url: 'https://git.kernel.org/stable/c/4a76953c3ed043797e81529b9395e9ca6f4c7609'
  - url: 'https://git.kernel.org/stable/c/1387f252a242a51bfbb6eace29c8f8db21b457da'
  - url: 'https://git.kernel.org/stable/c/10753da2d659dd425a6e620f47f86852d604f67f'
  - url: 'https://git.kernel.org/stable/c/3fa6fb5d771c992ebedbfa7331c6bcc6f33f89b7'
  - url: 'https://git.kernel.org/stable/c/27db54b90bcc7c37867fe664107fa25ea6a116e4'
tags:
  - cve.org
epss: 0.00195
epssPercentile: 0.09248
ingestedAt: '2026-11-06T18:00:12.561Z'
---

## Overview

In 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.

[1]: https://lore.kernel.org/bpf/ce5a6005-3c5e-4696-9e05-eba9461dc860@std.uestc.edu.cn/T/#u

## Affected

- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < a018f208ab7512380bd4cf670064d48cba00a1b1`
- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < 33373e1f378a501bc51aa73312f74295c84e3101`
- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < e2d3b7bab3748c811dc5750ce9a8d62bc7f90ed7`
- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < 4a76953c3ed043797e81529b9395e9ca6f4c7609`
- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < 1387f252a242a51bfbb6eace29c8f8db21b457da`
- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < 10753da2d659dd425a6e620f47f86852d604f67f`
- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < 3fa6fb5d771c992ebedbfa7331c6bcc6f33f89b7`
- `Linux >= 102740bd9436a3a6ba129af3a48271d794009fa5 < 27db54b90bcc7c37867fe664107fa25ea6a116e4`
- `Linux 4.15`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.