CVE-2026-64320 (GCVE-0-2026-64320)
Vulnerability from cvelistv5
Published
2026-07-25 08:49
Modified
2026-08-17 04:53
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page
nvmet_execute_disc_get_log_page() validates only the dword alignment
of the host-supplied Log Page Offset (lpo). The 64-bit offset is then
added to a small kzalloc'd buffer that holds the discovery log page
and the result is passed straight to nvmet_copy_to_sgl(), which
memcpy()s data_len bytes out to the host with no source-side bound
check:
u64 offset = nvmet_get_log_page_offset(req->cmd); /* 64-bit host */
size_t data_len = nvmet_get_log_page_len(req->cmd); /* 32-bit host */
...
if (offset & 0x3) { ... } /* only check */
...
alloc_len = sizeof(*hdr) + entry_size * discovery_log_entries(req);
buffer = kzalloc(alloc_len, GFP_KERNEL);
...
status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len);
The Discovery controller is unauthenticated -- nvmet_host_allowed()
returns true unconditionally for the discovery subsystem -- so the call
is reachable pre-authentication by any TCP/RDMA/FC peer that can reach
the nvmet target. With a discovery log page of ~1 KiB, an attacker
requesting up to 4 KiB starting at offset == alloc_len reads the next
slab page out and gets its content returned over the fabric (an
empirical run on a default nvmet-tcp loopback target leaked 81
canonical kernel pointers in one Get Log Page response). Pointing the
offset at unmapped kernel memory faults the in-kernel memcpy and
crashes (or panics, on panic_on_oops=1) the target host instead.
The attacker-controlled source-side offset pattern
"nvmet_copy_to_sgl(req, 0, buffer + ATTACKER_OFFSET, ...)" is unique
to nvmet_execute_disc_get_log_page in the entire nvmet codebase: every
other Get Log Page handler in admin-cmd.c either ignores lpo (and
silently starts every response at offset 0) or tracks a local
destination offset with a fixed source pointer.
Validate the host-supplied offset against the log page size, cap the
copy length to what is actually available, and zero-fill any remainder
of the host transfer buffer. The zero-fill matches the existing
short-response pattern in nvmet_execute_get_log_changed_ns()
(admin-cmd.c) and prevents leaking transport SGL contents when the
host asks for more bytes than the log page contains.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/nvme/target/discovery.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "33b974eb626154ae9348f2bac7de84cb2a3d9dd4",
"status": "affected",
"version": "a07b4970f464f13640e28e16dad6cfa33647cc99",
"versionType": "git"
},
{
"lessThan": "56c021a0869260d04c4b65d1471936aaf9177114",
"status": "affected",
"version": "a07b4970f464f13640e28e16dad6cfa33647cc99",
"versionType": "git"
},
{
"lessThan": "a29b316b9bbfd269f323ab4ba9906a894025680f",
"status": "affected",
"version": "a07b4970f464f13640e28e16dad6cfa33647cc99",
"versionType": "git"
},
{
"lessThan": "53cd102a7a56079b11b897835bd9b94c14e6322c",
"status": "affected",
"version": "a07b4970f464f13640e28e16dad6cfa33647cc99",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/nvme/target/discovery.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.8"
},
{
"lessThan": "4.8",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.96",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.96",
"versionStartIncluding": "4.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.39",
"versionStartIncluding": "4.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.4",
"versionStartIncluding": "4.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "4.8",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page\n\nnvmet_execute_disc_get_log_page() validates only the dword alignment\nof the host-supplied Log Page Offset (lpo). The 64-bit offset is then\nadded to a small kzalloc\u0027d buffer that holds the discovery log page\nand the result is passed straight to nvmet_copy_to_sgl(), which\nmemcpy()s data_len bytes out to the host with no source-side bound\ncheck:\n\n u64 offset = nvmet_get_log_page_offset(req-\u003ecmd); /* 64-bit host */\n size_t data_len = nvmet_get_log_page_len(req-\u003ecmd); /* 32-bit host */\n ...\n if (offset \u0026 0x3) { ... } /* only check */\n ...\n alloc_len = sizeof(*hdr) + entry_size * discovery_log_entries(req);\n buffer = kzalloc(alloc_len, GFP_KERNEL);\n ...\n status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len);\n\nThe Discovery controller is unauthenticated -- nvmet_host_allowed()\nreturns true unconditionally for the discovery subsystem -- so the call\nis reachable pre-authentication by any TCP/RDMA/FC peer that can reach\nthe nvmet target. With a discovery log page of ~1 KiB, an attacker\nrequesting up to 4 KiB starting at offset == alloc_len reads the next\nslab page out and gets its content returned over the fabric (an\nempirical run on a default nvmet-tcp loopback target leaked 81\ncanonical kernel pointers in one Get Log Page response). Pointing the\noffset at unmapped kernel memory faults the in-kernel memcpy and\ncrashes (or panics, on panic_on_oops=1) the target host instead.\n\nThe attacker-controlled source-side offset pattern\n\"nvmet_copy_to_sgl(req, 0, buffer + ATTACKER_OFFSET, ...)\" is unique\nto nvmet_execute_disc_get_log_page in the entire nvmet codebase: every\nother Get Log Page handler in admin-cmd.c either ignores lpo (and\nsilently starts every response at offset 0) or tracks a local\ndestination offset with a fixed source pointer.\n\nValidate the host-supplied offset against the log page size, cap the\ncopy length to what is actually available, and zero-fill any remainder\nof the host transfer buffer. The zero-fill matches the existing\nshort-response pattern in nvmet_execute_get_log_changed_ns()\n(admin-cmd.c) and prevents leaking transport SGL contents when the\nhost asks for more bytes than the log page contains."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The vulnerable discovery command is remotely reachable through routable NVMe/TCP, as well as NVMe/RDMA and FC transports.\nAC:L - The attacker controls the protocol sequence, transfer length, and aligned 64-bit offset, with no race or condition outside their control.\nPR:N - The discovery subsystem accepts every Host NQN and explicitly skips DH-HMAC-CHAP authentication, making the command reachable pre-authentication.\nUI:N - No victim action is required after the NVMe-oF target port is available.\nS:U - The disclosure and crash affect the vulnerable target kernel within the same security authority.\nC:H - The unbounded offset permits repeated multi-kilobyte kernel heap disclosures; testing cited by the fix exposed 81 canonical kernel pointers in one response.\nI:N - The primitive reads target memory into transport response pages but provides no attacker-selected write to target memory.\nA:H - An offset resolving to unmapped or noncanonical memory faults the in-kernel memcpy, causing an oops or target-host panic."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:53:20.999Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4"
},
{
"url": "https://git.kernel.org/stable/c/56c021a0869260d04c4b65d1471936aaf9177114"
},
{
"url": "https://git.kernel.org/stable/c/a29b316b9bbfd269f323ab4ba9906a894025680f"
},
{
"url": "https://git.kernel.org/stable/c/53cd102a7a56079b11b897835bd9b94c14e6322c"
}
],
"title": "nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64320",
"datePublished": "2026-07-25T08:49:48.908Z",
"dateReserved": "2026-07-19T15:36:31.780Z",
"dateUpdated": "2026-08-17T04:53:20.999Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…