CVE-2025-68751 (GCVE-0-2025-68751)
Vulnerability from cvelistv5 – Published: 2026-01-05 09:32 – Updated: 2026-01-05 09:32
VLAI?
Title
s390/fpu: Fix false-positive kmsan report in fpu_vstl()
Summary
In the Linux kernel, the following vulnerability has been resolved:
s390/fpu: Fix false-positive kmsan report in fpu_vstl()
A false-positive kmsan report is detected when running ping command.
An inline assembly instruction 'vstl' can write varied amount of bytes
depending on value of 'index' argument. If 'index' > 0, 'vstl' writes
at least 2 bytes.
clang generates kmsan write helper call depending on inline assembly
constraints. Constraints are evaluated compile-time, but value of
'index' argument is known only at runtime.
clang currently generates call to __msan_instrument_asm_store with 1 byte
as size. Manually call kmsan function to indicate correct amount of bytes
written and fix false-positive report.
This change fixes following kmsan reports:
[ 36.563119] =====================================================
[ 36.563594] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70
[ 36.563852] virtqueue_add+0x35c6/0x7c70
[ 36.564016] virtqueue_add_outbuf+0xa0/0xb0
[ 36.564266] start_xmit+0x288c/0x4a20
[ 36.564460] dev_hard_start_xmit+0x302/0x900
[ 36.564649] sch_direct_xmit+0x340/0xea0
[ 36.564894] __dev_queue_xmit+0x2e94/0x59b0
[ 36.565058] neigh_resolve_output+0x936/0xb40
[ 36.565278] __neigh_update+0x2f66/0x3a60
[ 36.565499] neigh_update+0x52/0x60
[ 36.565683] arp_process+0x1588/0x2de0
[ 36.565916] NF_HOOK+0x1da/0x240
[ 36.566087] arp_rcv+0x3e4/0x6e0
[ 36.566306] __netif_receive_skb_list_core+0x1374/0x15a0
[ 36.566527] netif_receive_skb_list_internal+0x1116/0x17d0
[ 36.566710] napi_complete_done+0x376/0x740
[ 36.566918] virtnet_poll+0x1bae/0x2910
[ 36.567130] __napi_poll+0xf4/0x830
[ 36.567294] net_rx_action+0x97c/0x1ed0
[ 36.567556] handle_softirqs+0x306/0xe10
[ 36.567731] irq_exit_rcu+0x14c/0x2e0
[ 36.567910] do_io_irq+0xd4/0x120
[ 36.568139] io_int_handler+0xc2/0xe8
[ 36.568299] arch_cpu_idle+0xb0/0xc0
[ 36.568540] arch_cpu_idle+0x76/0xc0
[ 36.568726] default_idle_call+0x40/0x70
[ 36.568953] do_idle+0x1d6/0x390
[ 36.569486] cpu_startup_entry+0x9a/0xb0
[ 36.569745] rest_init+0x1ea/0x290
[ 36.570029] start_kernel+0x95e/0xb90
[ 36.570348] startup_continue+0x2e/0x40
[ 36.570703]
[ 36.570798] Uninit was created at:
[ 36.571002] kmem_cache_alloc_node_noprof+0x9e8/0x10e0
[ 36.571261] kmalloc_reserve+0x12a/0x470
[ 36.571553] __alloc_skb+0x310/0x860
[ 36.571844] __ip_append_data+0x483e/0x6a30
[ 36.572170] ip_append_data+0x11c/0x1e0
[ 36.572477] raw_sendmsg+0x1c8c/0x2180
[ 36.572818] inet_sendmsg+0xe6/0x190
[ 36.573142] __sys_sendto+0x55e/0x8e0
[ 36.573392] __s390x_sys_socketcall+0x19ae/0x2ba0
[ 36.573571] __do_syscall+0x12e/0x240
[ 36.573823] system_call+0x6e/0x90
[ 36.573976]
[ 36.574017] Byte 35 of 98 is uninitialized
[ 36.574082] Memory access of size 98 starts at 0000000007aa0012
[ 36.574218]
[ 36.574325] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G B N 6.17.0-dirty #16 NONE
[ 36.574541] Tainted: [B]=BAD_PAGE, [N]=TEST
[ 36.574617] Hardware name: IBM 3931 A01 703 (KVM/Linux)
[ 36.574755] =====================================================
[ 63.532541] =====================================================
[ 63.533639] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70
[ 63.533989] virtqueue_add+0x35c6/0x7c70
[ 63.534940] virtqueue_add_outbuf+0xa0/0xb0
[ 63.535861] start_xmit+0x288c/0x4a20
[ 63.536708] dev_hard_start_xmit+0x302/0x900
[ 63.537020] sch_direct_xmit+0x340/0xea0
[ 63.537997] __dev_queue_xmit+0x2e94/0x59b0
[ 63.538819] neigh_resolve_output+0x936/0xb40
[ 63.539793] ip_finish_output2+0x1ee2/0x2200
[ 63.540784] __ip_finish_output+0x272/0x7a0
[ 63.541765] ip_finish_output+0x4e/0x5e0
[ 63.542791] ip_output+0x166/0x410
[ 63.543771] ip_push_pending_frames+0x1a2/0x470
[ 63.544753] raw_sendmsg+0x1f06/0x2180
[ 63.545033] inet_sendmsg+0xe6/0x190
[ 63.546006] __sys_sendto+0x55e/0x8e0
---truncated---
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Affected:
dcd3e1de9d17dc43dfed87a9fc814b9dec508043 , < 946357a538bb47740635c25520924351d2d91544
(git)
Affected: dcd3e1de9d17dc43dfed87a9fc814b9dec508043 , < 13dcd6308cb8f67134ee5d5d762b2a66363c695b (git) Affected: dcd3e1de9d17dc43dfed87a9fc814b9dec508043 , < 14e4e4175b64dd9216b522f6ece8af6997d063b2 (git) |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/s390/include/asm/fpu-insn.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "946357a538bb47740635c25520924351d2d91544",
"status": "affected",
"version": "dcd3e1de9d17dc43dfed87a9fc814b9dec508043",
"versionType": "git"
},
{
"lessThan": "13dcd6308cb8f67134ee5d5d762b2a66363c695b",
"status": "affected",
"version": "dcd3e1de9d17dc43dfed87a9fc814b9dec508043",
"versionType": "git"
},
{
"lessThan": "14e4e4175b64dd9216b522f6ece8af6997d063b2",
"status": "affected",
"version": "dcd3e1de9d17dc43dfed87a9fc814b9dec508043",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/s390/include/asm/fpu-insn.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.9"
},
{
"lessThan": "6.9",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.17.*",
"status": "unaffected",
"version": "6.17.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.2",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.19-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.17.13",
"versionStartIncluding": "6.9",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.2",
"versionStartIncluding": "6.9",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19-rc1",
"versionStartIncluding": "6.9",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/fpu: Fix false-positive kmsan report in fpu_vstl()\n\nA false-positive kmsan report is detected when running ping command.\n\nAn inline assembly instruction \u0027vstl\u0027 can write varied amount of bytes\ndepending on value of \u0027index\u0027 argument. If \u0027index\u0027 \u003e 0, \u0027vstl\u0027 writes\nat least 2 bytes.\n\nclang generates kmsan write helper call depending on inline assembly\nconstraints. Constraints are evaluated compile-time, but value of\n\u0027index\u0027 argument is known only at runtime.\n\nclang currently generates call to __msan_instrument_asm_store with 1 byte\nas size. Manually call kmsan function to indicate correct amount of bytes\nwritten and fix false-positive report.\n\nThis change fixes following kmsan reports:\n\n[ 36.563119] =====================================================\n[ 36.563594] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70\n[ 36.563852] virtqueue_add+0x35c6/0x7c70\n[ 36.564016] virtqueue_add_outbuf+0xa0/0xb0\n[ 36.564266] start_xmit+0x288c/0x4a20\n[ 36.564460] dev_hard_start_xmit+0x302/0x900\n[ 36.564649] sch_direct_xmit+0x340/0xea0\n[ 36.564894] __dev_queue_xmit+0x2e94/0x59b0\n[ 36.565058] neigh_resolve_output+0x936/0xb40\n[ 36.565278] __neigh_update+0x2f66/0x3a60\n[ 36.565499] neigh_update+0x52/0x60\n[ 36.565683] arp_process+0x1588/0x2de0\n[ 36.565916] NF_HOOK+0x1da/0x240\n[ 36.566087] arp_rcv+0x3e4/0x6e0\n[ 36.566306] __netif_receive_skb_list_core+0x1374/0x15a0\n[ 36.566527] netif_receive_skb_list_internal+0x1116/0x17d0\n[ 36.566710] napi_complete_done+0x376/0x740\n[ 36.566918] virtnet_poll+0x1bae/0x2910\n[ 36.567130] __napi_poll+0xf4/0x830\n[ 36.567294] net_rx_action+0x97c/0x1ed0\n[ 36.567556] handle_softirqs+0x306/0xe10\n[ 36.567731] irq_exit_rcu+0x14c/0x2e0\n[ 36.567910] do_io_irq+0xd4/0x120\n[ 36.568139] io_int_handler+0xc2/0xe8\n[ 36.568299] arch_cpu_idle+0xb0/0xc0\n[ 36.568540] arch_cpu_idle+0x76/0xc0\n[ 36.568726] default_idle_call+0x40/0x70\n[ 36.568953] do_idle+0x1d6/0x390\n[ 36.569486] cpu_startup_entry+0x9a/0xb0\n[ 36.569745] rest_init+0x1ea/0x290\n[ 36.570029] start_kernel+0x95e/0xb90\n[ 36.570348] startup_continue+0x2e/0x40\n[ 36.570703]\n[ 36.570798] Uninit was created at:\n[ 36.571002] kmem_cache_alloc_node_noprof+0x9e8/0x10e0\n[ 36.571261] kmalloc_reserve+0x12a/0x470\n[ 36.571553] __alloc_skb+0x310/0x860\n[ 36.571844] __ip_append_data+0x483e/0x6a30\n[ 36.572170] ip_append_data+0x11c/0x1e0\n[ 36.572477] raw_sendmsg+0x1c8c/0x2180\n[ 36.572818] inet_sendmsg+0xe6/0x190\n[ 36.573142] __sys_sendto+0x55e/0x8e0\n[ 36.573392] __s390x_sys_socketcall+0x19ae/0x2ba0\n[ 36.573571] __do_syscall+0x12e/0x240\n[ 36.573823] system_call+0x6e/0x90\n[ 36.573976]\n[ 36.574017] Byte 35 of 98 is uninitialized\n[ 36.574082] Memory access of size 98 starts at 0000000007aa0012\n[ 36.574218]\n[ 36.574325] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G B N 6.17.0-dirty #16 NONE\n[ 36.574541] Tainted: [B]=BAD_PAGE, [N]=TEST\n[ 36.574617] Hardware name: IBM 3931 A01 703 (KVM/Linux)\n[ 36.574755] =====================================================\n\n[ 63.532541] =====================================================\n[ 63.533639] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70\n[ 63.533989] virtqueue_add+0x35c6/0x7c70\n[ 63.534940] virtqueue_add_outbuf+0xa0/0xb0\n[ 63.535861] start_xmit+0x288c/0x4a20\n[ 63.536708] dev_hard_start_xmit+0x302/0x900\n[ 63.537020] sch_direct_xmit+0x340/0xea0\n[ 63.537997] __dev_queue_xmit+0x2e94/0x59b0\n[ 63.538819] neigh_resolve_output+0x936/0xb40\n[ 63.539793] ip_finish_output2+0x1ee2/0x2200\n[ 63.540784] __ip_finish_output+0x272/0x7a0\n[ 63.541765] ip_finish_output+0x4e/0x5e0\n[ 63.542791] ip_output+0x166/0x410\n[ 63.543771] ip_push_pending_frames+0x1a2/0x470\n[ 63.544753] raw_sendmsg+0x1f06/0x2180\n[ 63.545033] inet_sendmsg+0xe6/0x190\n[ 63.546006] __sys_sendto+0x55e/0x8e0\n---truncated---"
}
],
"providerMetadata": {
"dateUpdated": "2026-01-05T09:32:25.534Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/946357a538bb47740635c25520924351d2d91544"
},
{
"url": "https://git.kernel.org/stable/c/13dcd6308cb8f67134ee5d5d762b2a66363c695b"
},
{
"url": "https://git.kernel.org/stable/c/14e4e4175b64dd9216b522f6ece8af6997d063b2"
}
],
"title": "s390/fpu: Fix false-positive kmsan report in fpu_vstl()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2025-68751",
"datePublished": "2026-01-05T09:32:25.534Z",
"dateReserved": "2025-12-24T10:30:51.032Z",
"dateUpdated": "2026-01-05T09:32:25.534Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2025-68751\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-01-05T10:15:56.050\",\"lastModified\":\"2026-01-08T18:09:49.800\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\ns390/fpu: Fix false-positive kmsan report in fpu_vstl()\\n\\nA false-positive kmsan report is detected when running ping command.\\n\\nAn inline assembly instruction \u0027vstl\u0027 can write varied amount of bytes\\ndepending on value of \u0027index\u0027 argument. If \u0027index\u0027 \u003e 0, \u0027vstl\u0027 writes\\nat least 2 bytes.\\n\\nclang generates kmsan write helper call depending on inline assembly\\nconstraints. Constraints are evaluated compile-time, but value of\\n\u0027index\u0027 argument is known only at runtime.\\n\\nclang currently generates call to __msan_instrument_asm_store with 1 byte\\nas size. Manually call kmsan function to indicate correct amount of bytes\\nwritten and fix false-positive report.\\n\\nThis change fixes following kmsan reports:\\n\\n[ 36.563119] =====================================================\\n[ 36.563594] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70\\n[ 36.563852] virtqueue_add+0x35c6/0x7c70\\n[ 36.564016] virtqueue_add_outbuf+0xa0/0xb0\\n[ 36.564266] start_xmit+0x288c/0x4a20\\n[ 36.564460] dev_hard_start_xmit+0x302/0x900\\n[ 36.564649] sch_direct_xmit+0x340/0xea0\\n[ 36.564894] __dev_queue_xmit+0x2e94/0x59b0\\n[ 36.565058] neigh_resolve_output+0x936/0xb40\\n[ 36.565278] __neigh_update+0x2f66/0x3a60\\n[ 36.565499] neigh_update+0x52/0x60\\n[ 36.565683] arp_process+0x1588/0x2de0\\n[ 36.565916] NF_HOOK+0x1da/0x240\\n[ 36.566087] arp_rcv+0x3e4/0x6e0\\n[ 36.566306] __netif_receive_skb_list_core+0x1374/0x15a0\\n[ 36.566527] netif_receive_skb_list_internal+0x1116/0x17d0\\n[ 36.566710] napi_complete_done+0x376/0x740\\n[ 36.566918] virtnet_poll+0x1bae/0x2910\\n[ 36.567130] __napi_poll+0xf4/0x830\\n[ 36.567294] net_rx_action+0x97c/0x1ed0\\n[ 36.567556] handle_softirqs+0x306/0xe10\\n[ 36.567731] irq_exit_rcu+0x14c/0x2e0\\n[ 36.567910] do_io_irq+0xd4/0x120\\n[ 36.568139] io_int_handler+0xc2/0xe8\\n[ 36.568299] arch_cpu_idle+0xb0/0xc0\\n[ 36.568540] arch_cpu_idle+0x76/0xc0\\n[ 36.568726] default_idle_call+0x40/0x70\\n[ 36.568953] do_idle+0x1d6/0x390\\n[ 36.569486] cpu_startup_entry+0x9a/0xb0\\n[ 36.569745] rest_init+0x1ea/0x290\\n[ 36.570029] start_kernel+0x95e/0xb90\\n[ 36.570348] startup_continue+0x2e/0x40\\n[ 36.570703]\\n[ 36.570798] Uninit was created at:\\n[ 36.571002] kmem_cache_alloc_node_noprof+0x9e8/0x10e0\\n[ 36.571261] kmalloc_reserve+0x12a/0x470\\n[ 36.571553] __alloc_skb+0x310/0x860\\n[ 36.571844] __ip_append_data+0x483e/0x6a30\\n[ 36.572170] ip_append_data+0x11c/0x1e0\\n[ 36.572477] raw_sendmsg+0x1c8c/0x2180\\n[ 36.572818] inet_sendmsg+0xe6/0x190\\n[ 36.573142] __sys_sendto+0x55e/0x8e0\\n[ 36.573392] __s390x_sys_socketcall+0x19ae/0x2ba0\\n[ 36.573571] __do_syscall+0x12e/0x240\\n[ 36.573823] system_call+0x6e/0x90\\n[ 36.573976]\\n[ 36.574017] Byte 35 of 98 is uninitialized\\n[ 36.574082] Memory access of size 98 starts at 0000000007aa0012\\n[ 36.574218]\\n[ 36.574325] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G B N 6.17.0-dirty #16 NONE\\n[ 36.574541] Tainted: [B]=BAD_PAGE, [N]=TEST\\n[ 36.574617] Hardware name: IBM 3931 A01 703 (KVM/Linux)\\n[ 36.574755] =====================================================\\n\\n[ 63.532541] =====================================================\\n[ 63.533639] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70\\n[ 63.533989] virtqueue_add+0x35c6/0x7c70\\n[ 63.534940] virtqueue_add_outbuf+0xa0/0xb0\\n[ 63.535861] start_xmit+0x288c/0x4a20\\n[ 63.536708] dev_hard_start_xmit+0x302/0x900\\n[ 63.537020] sch_direct_xmit+0x340/0xea0\\n[ 63.537997] __dev_queue_xmit+0x2e94/0x59b0\\n[ 63.538819] neigh_resolve_output+0x936/0xb40\\n[ 63.539793] ip_finish_output2+0x1ee2/0x2200\\n[ 63.540784] __ip_finish_output+0x272/0x7a0\\n[ 63.541765] ip_finish_output+0x4e/0x5e0\\n[ 63.542791] ip_output+0x166/0x410\\n[ 63.543771] ip_push_pending_frames+0x1a2/0x470\\n[ 63.544753] raw_sendmsg+0x1f06/0x2180\\n[ 63.545033] inet_sendmsg+0xe6/0x190\\n[ 63.546006] __sys_sendto+0x55e/0x8e0\\n---truncated---\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/13dcd6308cb8f67134ee5d5d762b2a66363c695b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/14e4e4175b64dd9216b522f6ece8af6997d063b2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/946357a538bb47740635c25520924351d2d91544\",\"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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