# CVE-2026-31507

> Vulnerability · severity: **HIGH** (CVSS 7.8).

## Description

In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer

smc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores
the pointer in pipe_buffer.private.  The pipe_buf_operations for these
buffers used .get = generic_pipe_buf_get, which only increments the page
reference count when tee(2) duplicates a pipe buffer.  The smc_spd_priv
pointer itself was not handled, so after tee() both the original and the
cloned pipe_buffer share the same smc_spd_priv *.

When both pipes are subsequently released, smc_rx_pipe_buf_release() is
called twice against the same object:

  1st call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [correct]
  2nd call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [UAF]

KASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which
then escalates to a NULL-pointer dereference and kernel panic via
smc_rx_update_consumer() when it chases the freed priv->smc pointer:

  BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0
  Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74
  Call Trace:
   <TASK>
   dump_stack_lvl+0x53/0x70
   print_report+0xce/0x650
   kasan_report+0xc6/0x100
   smc_rx_pipe_buf_release+0x78/0x2a0
   free_pipe_info+0xd4/0x130
   pipe_release+0x142/0x160
   __fput+0x1c6/0x490
   __x64_sys_close+0x4f/0x90
   do_syscall_64+0xa6/0x1a0
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   </TASK>

  BUG: kernel NULL pointer dereference, address: 0000000000000020
  RIP: 0010:smc_rx_update_consumer+0x8d/0x350
  Call Trace:
   <TASK>
   smc_rx_pipe_buf_release+0x121/0x2a0
   free_pipe_info+0xd4/0x130
   pipe_release+0x142/0x160
   __fput+0x1c6/0x490
   __x64_sys_close+0x4f/0x90
   do_syscall_64+0xa6/0x1a0
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   </TASK>
  Kernel panic - not syncing: Fatal exception

Beyond the memory-safety problem, duplicating an SMC splice buffer is
semantically questio

## Key facts

- **CVE ID:** CVE-2026-31507
- **Published:** 2026-04-22
- **CVSS severity:** HIGH
- **CVSS base score:** 7.8
- **CWE codes:** CWE-415

## Affected products

- `linux:linux_kernel`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31507

## Citation

> AI Analytics. CVE-2026-31507. Retrieved 2026-08-08 from https://api.ai-analytics.org/cve/CVE-2026-31507. Derived from NIST NVD. Licensed CC0.

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