CVE-2026-64456— Linux kernel 安全漏洞
一分钟漏洞结论
影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 2.6.26版本存在安全漏洞，该漏洞源于hwrng: virtio驱动中copy_data()函数未重新验证设备报告的used.len，可能导致越界读取和信息泄露。
影响版本矩阵 18
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | f7f510ec195781c857ab76366a3e1c59e1caae42< 3aa3e89cf80721c8d382b4c1a2b70a0449dad4a5 |
affected |
f7f510ec195781c857ab76366a3e1c59e1caae42< 63335e7b638ae70028ae285bb95153874a8bc852 |
affected | ||
f7f510ec195781c857ab76366a3e1c59e1caae42< 2e788948ff2a13358a303af112497a63201c5739 |
affected | ||
f7f510ec195781c857ab76366a3e1c59e1caae42< fde19b0d4eeabae042519313c843fe6f27d41e9d |
affected | ||
f7f510ec195781c857ab76366a3e1c59e1caae42< 81dd21b5f0c299cc7b5bf84f04a61938559d20e6 |
affected | ||
f7f510ec195781c857ab76366a3e1c59e1caae42< 285e17c44e3873a73460f294acbd64018ff64385 |
affected | ||
f7f510ec195781c857ab76366a3e1c59e1caae42< 92d5736a62040ec1cfff23ea57e6599301690ad5 |
affected | ||
f7f510ec195781c857ab76366a3e1c59e1caae42< e3046eeada299f917a8ad883af4434bfb86556b1 |
affected | ||
| … +10 条更多 | |||
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一、 漏洞 CVE-2026-64456 基础信息
漏洞信息
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Vulnerability Title
hwrng: virtio: clamp device-reported used.len at copy_data()
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
hwrng: virtio: clamp device-reported used.len at copy_data()
random_recv_done() stores the device-reported used.len directly into
vi->data_avail. copy_data() then indexes vi->data[] using
vi->data_idx (advanced by previous copy_data() calls) and issues a
memcpy() without re-validating either value against the posted
buffer size sizeof(vi->data) (SMP_CACHE_BYTES bytes, typically 32
or 64).
A malicious or buggy virtio-rng backend can set used.len beyond
sizeof(vi->data), steering the memcpy() past the end of the inline
array into adjacent kmalloc-1k slab bytes. hwrng_fillfn() mixes
those bytes into the guest RNG, and guest root can also observe
them directly via /dev/hwrng.
Concrete impact is inside the guest:
- Memory-safety / hardening: any virtio-rng backend that
over-reports used.len causes the driver to read past vi->data
into unrelated slab contents. hwrng_fillfn() is a kernel thread
that runs as soon as the device is probed; no guest userspace
interaction is required to first-trigger the OOB.
- Cross-boundary leak (confidential-compute threat model): a
malicious hypervisor cooperating with a malicious or compromised
guest root userspace can use /dev/hwrng as a leak channel for
guest-kernel heap data. The host sets a large used.len, guest
root reads /dev/hwrng, and the returned bytes contain guest
kernel slab contents that were adjacent to vi->data. In
practice, confidential-compute guests (SEV-SNP, TDX) usually
disable virtio-rng entirely, so this path is narrow, but the
fix is still worth carrying because the underlying
memory-safety bug contaminates the guest RNG on any host.
KASAN confirms the OOB on a 7.1-rc4 guest whose virtio-rng backend
has been patched to report used.len = 0x10000:
BUG: KASAN: slab-out-of-bounds in virtio_read+0x394/0x5d0
Read of size 64 at addr ffff88800ae0ba20 by task hwrng/52
Call Trace:
__asan_memcpy+0x23/0x60
virtio_read+0x394/0x5d0
hwrng_fillfn+0xb2/0x470
kthread+0x2cc/0x3a0
Allocated by task 1:
probe_common+0xa5/0x660
virtio_dev_probe+0x549/0xbc0
The buggy address belongs to the object at ffff88800ae0b800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes to the right of
allocated 544-byte region [ffff88800ae0b800, ffff88800ae0ba20)
Same class of bug as commit c04db81cd028 ("net/9p: Fix buffer
overflow in USB transport layer"), which hardened
usb9pfs_rx_complete() against unchecked device-reported length in
the USB 9p transport.
With the clamp at point of use and array_index_nospec() in place,
the same harness boots cleanly: copy_data() returns zero for the
bogus report, the device-supplied bytes after data_idx are
discarded, and the driver issues a fresh request.
来源: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 2.6.26版本存在安全漏洞，该漏洞源于hwrng: virtio驱动中copy_data()函数未重新验证设备报告的used.len，可能导致越界读取和信息泄露。
来源: 中国国家信息安全漏洞库 CNNVD
CVSS Information
N/A
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Type
N/A
来源: 中国国家信息安全漏洞库 CNNVD
受影响产品
二、漏洞 CVE-2026-64456 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2026-64456 补丁与修复 (7)
同批安全公告 · Linux · 2026-07-25 · 共 274 条
| CVE-2026-64355 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64459 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64303 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64439 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64410 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64399 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64397 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64391 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64387 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64386 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64385 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64383 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64384 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64268 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64523 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64269 | 9.1 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64450 | 9.1 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64257 | 9.1 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64393 | 9.1 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-64392 | 9.1 CRITICAL | Linux kernel 安全漏洞 |
显示前 20 条，共 274 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-64456
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