Critical severity · published Jul 25, 2026
CVE-2026-64320
nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page
9.1
CVSS
0.7%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 55% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
4.8 before 6.12.96; 6.13 before 6.18.39; 6.19 before 7.1.4 · source: NVD
LI
Linux · Linux
a07b4970f464f13640e28e16dad6cfa33647cc99 before 8ae9bb92fc9a712a8d32da9c5fd657101f9b260b; a07b4970f464f13640e28e16dad6cfa33647cc99 before 33b974eb626154ae9348f2bac7de84cb2a3d9dd4; a07b4970f464f13640e28e16dad6cfa33647cc99 before 56c021a0869260d04c4b65d1471936aaf9177114; a07b4970f464f13640e28e16dad6cfa33647cc99 before a29b316b9bbfd269f323ab4ba9906a894025680f; a07b4970f464f13640e28e16dad6cfa33647cc99 before 53cd102a7a56079b11b897835bd9b94c14e6322c; 4.8 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-64320
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-64320
Patch
https://git.kernel.org/stable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4
Patch
https://git.kernel.org/stable/c/53cd102a7a56079b11b897835bd9b94c14e6322c
Patch
https://git.kernel.org/stable/c/56c021a0869260d04c4b65d1471936aaf9177114
git.kernel.org
https://git.kernel.org/stable/c/8ae9bb92fc9a712a8d32da9c5fd657101f9b260b
Patch
https://git.kernel.org/stable/c/a29b316b9bbfd269f323ab4ba9906a894025680f
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