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CVE-2026-64320— nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 4.8版本存在安全漏洞，该漏洞源于nvmet_execute_disc_get_log_page函数对主机提供的偏移量仅验证dword对齐，未进行边界检查，导致越界堆读取，未认证攻击者可利用此漏洞读取内核内存或导致系统崩溃。

CVSS 9.1 · Critical EPSS 0.75% · P54

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux a07b4970f464f13640e28e16dad6cfa33647cc99< 33b974eb626154ae9348f2bac7de84cb2a3d9dd4 affected
a07b4970f464f13640e28e16dad6cfa33647cc99< 56c021a0869260d04c4b65d1471936aaf9177114 affected
a07b4970f464f13640e28e16dad6cfa33647cc99< a29b316b9bbfd269f323ab4ba9906a894025680f affected
a07b4970f464f13640e28e16dad6cfa33647cc99< 53cd102a7a56079b11b897835bd9b94c14e6322c affected
4.8 affected
< 4.8 unaffected
6.12.96≤ 6.12.* unaffected
6.18.39≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-64320

Vulnerability Information
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Vulnerability Title
nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 4.8版本存在安全漏洞，该漏洞源于nvmet_execute_disc_get_log_page函数对主机提供的偏移量仅验证dword对齐，未进行边界检查，导致越界堆读取，未认证攻击者可利用此漏洞读取内核内存或导致系统崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux a07b4970f464f13640e28e16dad6cfa33647cc99 ~ 33b974eb626154ae9348f2bac7de84cb2a3d9dd4 -
Linux Linux 4.8 -

II. Public POCs for CVE-2026-64320

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III. Intelligence Information for CVE-2026-64320

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Patches & Fixes for CVE-2026-64320 (4)

Same Patch Batch · Linux · 2026-07-25 · 274 CVEs total

CVE-2026-64355 9.8 CRITICAL bpf: Reject fragmented frames in devmap
CVE-2026-64459 9.8 CRITICAL tcp: restore RCU grace period in tcp_ao_destroy_sock
CVE-2026-64303 9.8 CRITICAL spi: fsl-lpspi: terminate the RX channel on TX prepare failure path
CVE-2026-64439 9.8 CRITICAL crypto: krb5 - filter out async aead implementations at alloc
CVE-2026-64410 9.8 CRITICAL netfilter: flowtable: IPIP tunnel hardware offload is not yet support
CVE-2026-64399 9.8 CRITICAL ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE
CVE-2026-64397 9.8 CRITICAL ksmbd: serialize QUERY_DIRECTORY requests per file
CVE-2026-64391 9.8 CRITICAL ksmbd: use opener credentials for ADS I/O
CVE-2026-64387 9.8 CRITICAL smb: client: fix query directory replay double-free
CVE-2026-64386 9.8 CRITICAL smb: client: fix query_info() replay double-free
CVE-2026-64385 9.8 CRITICAL smb: client: fix double-free in SMB2_ioctl() replay
CVE-2026-64383 9.8 CRITICAL smb: client: fix double-free in SMB2_flush() replay
CVE-2026-64384 9.8 CRITICAL smb: client: fix change notify replay double-free
CVE-2026-64268 9.8 CRITICAL RDMA/siw: bound Read Response placement to the RREAD length
CVE-2026-64523 9.8 CRITICAL net/handshake: Take a long-lived file reference at submit
CVE-2026-64269 9.1 CRITICAL RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg
CVE-2026-64319 9.1 CRITICAL nvmet-auth: validate reply message payload bounds against transfer length
CVE-2026-64257 9.1 CRITICAL smb: client: reject overlapping data areas in SMB2 responses
CVE-2026-64393 9.1 CRITICAL ksmbd: run set info with opener credentials
CVE-2026-64392 9.1 CRITICAL ksmbd: use opener credentials for delete-on-close

Showing top 20 of 274 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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