GHSA-XF3Q-F592-RMGX
Vulnerability from github – Published: 2026-04-22 15:31 – Updated: 2026-04-27 15:30In 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: 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
BUG: kernel NULL pointer dereference, address: 0000000000000020 RIP: 0010:smc_rx_update_consumer+0x8d/0x350 Call Trace: 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 Kernel panic - not syncing: Fatal exception
Beyond the memory-safety problem, duplicating an SMC splice buffer is semantically questionable: smc_rx_update_cons() would advance the consumer cursor twice for the same data, corrupting receive-window accounting. A refcount on smc_spd_priv could fix the double-free, but the cursor-accounting issue would still need to be addressed separately.
The .get callback is invoked by both tee(2) and splice_pipe_to_pipe() for partial transfers; both will now return -EFAULT. Users who need to duplicate SMC socket data must use a copy-based read path.
{
"affected": [],
"aliases": [
"CVE-2026-31507"
],
"database_specific": {
"cwe_ids": [
"CWE-415"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-22T14:16:49Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer\n\nsmc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores\nthe pointer in pipe_buffer.private. The pipe_buf_operations for these\nbuffers used .get = generic_pipe_buf_get, which only increments the page\nreference count when tee(2) duplicates a pipe buffer. The smc_spd_priv\npointer itself was not handled, so after tee() both the original and the\ncloned pipe_buffer share the same smc_spd_priv *.\n\nWhen both pipes are subsequently released, smc_rx_pipe_buf_release() is\ncalled twice against the same object:\n\n 1st call: kfree(priv) sock_put(sk) smc_rx_update_cons() [correct]\n 2nd call: kfree(priv) sock_put(sk) smc_rx_update_cons() [UAF]\n\nKASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which\nthen escalates to a NULL-pointer dereference and kernel panic via\nsmc_rx_update_consumer() when it chases the freed priv-\u003esmc pointer:\n\n BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0\n Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74\n Call Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x53/0x70\n print_report+0xce/0x650\n kasan_report+0xc6/0x100\n smc_rx_pipe_buf_release+0x78/0x2a0\n free_pipe_info+0xd4/0x130\n pipe_release+0x142/0x160\n __fput+0x1c6/0x490\n __x64_sys_close+0x4f/0x90\n do_syscall_64+0xa6/0x1a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n\n BUG: kernel NULL pointer dereference, address: 0000000000000020\n RIP: 0010:smc_rx_update_consumer+0x8d/0x350\n Call Trace:\n \u003cTASK\u003e\n smc_rx_pipe_buf_release+0x121/0x2a0\n free_pipe_info+0xd4/0x130\n pipe_release+0x142/0x160\n __fput+0x1c6/0x490\n __x64_sys_close+0x4f/0x90\n do_syscall_64+0xa6/0x1a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n Kernel panic - not syncing: Fatal exception\n\nBeyond the memory-safety problem, duplicating an SMC splice buffer is\nsemantically questionable: smc_rx_update_cons() would advance the\nconsumer cursor twice for the same data, corrupting receive-window\naccounting. A refcount on smc_spd_priv could fix the double-free, but\nthe cursor-accounting issue would still need to be addressed separately.\n\nThe .get callback is invoked by both tee(2) and splice_pipe_to_pipe()\nfor partial transfers; both will now return -EFAULT. Users who need\nto duplicate SMC socket data must use a copy-based read path.",
"id": "GHSA-xf3q-f592-rmgx",
"modified": "2026-04-27T15:30:39Z",
"published": "2026-04-22T15:31:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31507"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/24dd586bb4cbba1889a50abe74143817a095c1c9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3cc76380fea749280c026f410af56a28aaac388a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/54c87a730157868543ebdfa0ecb21b4590ed23a5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7bcb974c771c863e8588cea0012ac204443a7126"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7e8916f46c2f48607f907fd401590093753a6bc5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/81acbd345d405994875d419d43b319fee0b9ad62"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/98ba5cb274768146e25ffbfde47753652c1c20d3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ae5575e660410c8d2c5d38fb28a0f37aea945676"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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