Bug 2507061 (CVE-2026-64320) - CVE-2026-64320 kernel: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page
Summary: CVE-2026-64320 kernel: nvmet: fix pre-auth out-of-bounds heap read in Discove...
Keywords:
Status: NEW
Alias: CVE-2026-64320
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-25 10:02 UTC by OSIDB Bzimport
Modified: 2026-09-08 09:25 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:59737 0 None None None 2026-08-26 03:58:50 UTC
Red Hat Product Errata RHSA-2026:59821 0 None None None 2026-08-26 05:34:23 UTC
Red Hat Product Errata RHSA-2026:61887 0 None None None 2026-09-01 07:31:14 UTC
Red Hat Product Errata RHSA-2026:64808 0 None None None 2026-09-08 09:25:27 UTC

Description OSIDB Bzimport 2026-07-25 10:02:59 UTC
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.

Comment 1 Mauro Matteo Cascella 2026-07-29 22:17:27 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072511-CVE-2026-64320-4b43@gregkh/T

Comment 4 errata-xmlrpc 2026-08-26 03:58:49 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:59737 https://access.redhat.com/errata/RHSA-2026:59737

Comment 5 errata-xmlrpc 2026-08-26 05:34:22 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:59821 https://access.redhat.com/errata/RHSA-2026:59821

Comment 6 errata-xmlrpc 2026-09-01 07:31:13 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:61887 https://access.redhat.com/errata/RHSA-2026:61887

Comment 7 errata-xmlrpc 2026-09-08 09:25:26 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:64808 https://access.redhat.com/errata/RHSA-2026:64808


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