CVE-2026-31507 (GCVE-0-2026-31507)
Vulnerability from cvelistv5 – Published: 2026-04-22 13:54 – Updated: 2026-04-22 13:54
VLAI?
Title
net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer
Summary
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 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.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux |
Affected:
9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < 7e8916f46c2f48607f907fd401590093753a6bc5
(git)
Affected: 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < ae5575e660410c8d2c5d38fb28a0f37aea945676 (git) Affected: 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < 98ba5cb274768146e25ffbfde47753652c1c20d3 (git) Affected: 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < 81acbd345d405994875d419d43b319fee0b9ad62 (git) Affected: 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < 7bcb974c771c863e8588cea0012ac204443a7126 (git) Affected: 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < 54c87a730157868543ebdfa0ecb21b4590ed23a5 (git) Affected: 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < 3cc76380fea749280c026f410af56a28aaac388a (git) Affected: 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f , < 24dd586bb4cbba1889a50abe74143817a095c1c9 (git) |
|||||||
|
|||||||||
{
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"version": "0",
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"version": "5.15.203",
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{
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"status": "unaffected",
"version": "6.1.168",
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{
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"status": "unaffected",
"version": "6.6.131",
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"cpeApplicability": [
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"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"providerMetadata": {
"dateUpdated": "2026-04-22T13:54:25.910Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"references": [
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"url": "https://git.kernel.org/stable/c/7e8916f46c2f48607f907fd401590093753a6bc5"
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{
"url": "https://git.kernel.org/stable/c/ae5575e660410c8d2c5d38fb28a0f37aea945676"
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"url": "https://git.kernel.org/stable/c/98ba5cb274768146e25ffbfde47753652c1c20d3"
},
{
"url": "https://git.kernel.org/stable/c/81acbd345d405994875d419d43b319fee0b9ad62"
},
{
"url": "https://git.kernel.org/stable/c/7bcb974c771c863e8588cea0012ac204443a7126"
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{
"url": "https://git.kernel.org/stable/c/54c87a730157868543ebdfa0ecb21b4590ed23a5"
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{
"url": "https://git.kernel.org/stable/c/3cc76380fea749280c026f410af56a28aaac388a"
},
{
"url": "https://git.kernel.org/stable/c/24dd586bb4cbba1889a50abe74143817a095c1c9"
}
],
"title": "net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer",
"x_generator": {
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}
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"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-31507",
"datePublished": "2026-04-22T13:54:25.910Z",
"dateReserved": "2026-03-09T15:48:24.106Z",
"dateUpdated": "2026-04-22T13:54:25.910Z",
"state": "PUBLISHED"
},
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"cve": "CVE-2026-31507",
"date": "2026-04-24",
"epss": "0.00024",
"percentile": "0.06773"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-31507\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-22T14:16:49.523\",\"lastModified\":\"2026-04-23T16:17:41.280\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/24dd586bb4cbba1889a50abe74143817a095c1c9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3cc76380fea749280c026f410af56a28aaac388a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/54c87a730157868543ebdfa0ecb21b4590ed23a5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7bcb974c771c863e8588cea0012ac204443a7126\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7e8916f46c2f48607f907fd401590093753a6bc5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/81acbd345d405994875d419d43b319fee0b9ad62\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/98ba5cb274768146e25ffbfde47753652c1c20d3\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ae5575e660410c8d2c5d38fb28a0f37aea945676\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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