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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-74382

net/sched: cls_bpf: prevent unbounded recursion in offload rollback

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Status
Published
Published
Updated
Assigning organization
Linux

Description

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 products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < a018f208ab7512380bd4cf670064d48cba00a1b1affected
  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < 33373e1f378a501bc51aa73312f74295c84e3101affected
  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < e2d3b7bab3748c811dc5750ce9a8d62bc7f90ed7affected
  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < 4a76953c3ed043797e81529b9395e9ca6f4c7609affected
  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < 1387f252a242a51bfbb6eace29c8f8db21b457daaffected
  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < 10753da2d659dd425a6e620f47f86852d604f67faffected
  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < 3fa6fb5d771c992ebedbfa7331c6bcc6f33f89b7affected
  • 102740bd9436a3a6ba129af3a48271d794009fa5 to < 27db54b90bcc7c37867fe664107fa25ea6a116e4affected

Linux Linux

Default version status: affected

  • 4.15affected
  • 0 to < 4.15unaffected
  • 5.10.261 to ≤ 5.10.*unaffected
  • 5.15.212 to ≤ 5.15.*unaffected
  • 6.1.178 to ≤ 6.1.*unaffected
  • 6.6.145 to ≤ 6.6.*unaffected
  • 6.12.97 to ≤ 6.12.*unaffected
  • 6.18.40 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References