CVE-2026-74691— Thunderbolt DMA路径清理漏洞
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。
在 Linux 内核中，已解决以下漏洞： 网络：Thunderbolt 驱动 - 在停止环形队列（rings）之前销毁 DMA 路径 函数在调用 之前，先停止两个环形队列并释放其帧缓冲区。然而， 会将环形队列的描述符基地址清零，而 会解除映射并释放帧所在的页面。因此，当 轮询跃点（hop）的“pending”（待处理）位时，任何仍在传输中的数据帧都无处可去（无法被正确排空/ draining）。 自该驱动被添加以来，销毁（teardown）序列一直是这种顺序。但初始化（setup）路径并非如此：提交 ff7cd07
可能的 ATT&CK 技术 1 AI
T1499 · Endpoint Denial of Service影响版本矩阵 16
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e< 7cce39109206bc5497e0953806563644b88bfc44 |
affected |
e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e< 0da9a6d27155ad072dd76db8cd637feead99a0e0 |
affected | ||
e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e< b5a21615f627c48dafaa6ef82a34a5b97a4352aa |
affected | ||
e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e< 103a9b663ac1cacb8465aeff18f84a247154a562 |
affected | ||
e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e< 4dd71cb0d23d40cb58fe4261c7bd183dca66caa0 |
affected | ||
e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e< 9a482b2b117e5fa656b6d24fc01799e8ac2d4368 |
affected | ||
e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e< 68bf02b6b4ad3f748c6db71fd77b6c0402d252f4 |
affected | ||
4.15 |
affected | ||
| … +8 条更多 | |||
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一、 漏洞 CVE-2026-74691 基础信息
漏洞信息
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Vulnerability Title
net: thunderbolt: Tear down DMA paths before stopping the rings
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
net: thunderbolt: Tear down DMA paths before stopping the rings
tbnet_tear_down() stops both rings and frees their frame buffers before
calling tb_xdomain_disable_paths(). tb_ring_stop() zeroes the ring's
descriptor base and tbnet_free_buffers() unmaps and frees the pages the
frames sit in, so by the time __tb_path_deactivate_hop() polls the hop's
'pending' bit, anything still in flight has nowhere to drain to.
The teardown sequence has been in this order since the driver was added.
The setup path has not: commit ff7cd07f3064 ("net: thunderbolt: Enable
DMA paths only after rings are enabled") moved the path enable to the end
of tbnet_connected_work() and documented why:
/* Both logins successful so enable the rings, high-speed DMA
* paths and start the network device queue.
*
* Note we enable the DMA paths last to make sure we have primed
* the Rx ring before any incoming packets are allowed to
* arrive.
*/
Teardown was never updated to match, so the rings and the paths now come
down in the same order they go up instead of in reverse.
On an ASMedia ASM4242 host router the 'pending' bit then never clears:
every teardown burns the full 500 ms timeout and
__tb_path_deactivate_hop() returns -ETIMEDOUT. Raising the timeout to
5 s does not help, so the hop is not slow to drain, it never drains
at all.
The failure is invisible above the thunderbolt core.
__tb_path_deactivate_hops() is void and only calls tb_port_warn();
tb_path_deactivate(), tb_tunnel_deactivate() and
__tb_disconnect_xdomain_paths() are void as well, and
tb_disconnect_xdomain_paths() ends in an unconditional "return 0". So
tb_xdomain_disable_paths() reports success and the netdev_warn() below
it never fires. Repeated teardowns eventually take the XDomain control
channel down, after which the peer node is gone and only a power cycle
brings the controller back.
Deactivating the paths first fixes it. Measured with kretprobes on a
stock v6.17 tree with no other patches applied, on a link that was up
and had just carried traffic:
before: __tb_path_deactivate_hop() returns 0 for the first hop, then
-ETIMEDOUT for the second 500335 us later
after: 0 for both, 525 us apart
Alternating the two orderings ABBA over three load levels, four
teardowns per arm: every teardown failed before the change (21 of 21
that ran), none failed after (0 of 24). The before arms ran short
because the link died partway through. The same split shows up when
the interface is enslaved to a bond instead of just brought down, which
is how I ran into this in the first place. Throughput and latency after
the change are unchanged.
Hosts whose routers drain the hop despite the stale descriptor base see
no functional difference, since the paths end up deactivated either way.
来源: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
受影响产品
二、漏洞 CVE-2026-74691 的公开POC
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|---|
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CVE-2026-74691 补丁与修复 (6)
CVE-2026-74691 其他参考 (1)
同批安全公告 · Linux · 2026-08-22 · 共 150 条
| CVE-2026-74705 | 10.0 CRITICAL | UDP隧道分段潜在使用-after-free漏洞 |
| CVE-2026-74612 | 10.0 CRITICAL | Linux内核veth模块SKB长度计算漏洞 |
| CVE-2026-74587 | 9.8 CRITICAL | SCTP 缓存 ASCONF 块使用后释放漏洞 |
| CVE-2026-74591 | 9.8 CRITICAL | Linux 内核文件映射恢复索引前重试导致漏洞 |
| CVE-2026-74608 | 9.8 CRITICAL | SMB客户端cifs_try_adding_channels函数中的释放后使用漏洞 |
| CVE-2026-74662 | 9.8 CRITICAL | Linux inet frags 定时器竞争条件漏洞 |
| CVE-2026-74669 | 9.8 CRITICAL | Linux IPVS IPv4选项后重定位隧道ICMP错误 |
| CVE-2026-74628 | 9.8 CRITICAL | Linux内核 x25 远程计时器释放后使用漏洞 |
| CVE-2026-74688 | 9.8 CRITICAL | SCTP传输控制块移除漏洞 |
| CVE-2026-74597 | 9.8 CRITICAL | Linux ip6_tunnel skb2->cb[]未清除漏洞 |
| CVE-2026-74617 | 9.8 CRITICAL | dibs: 在dibs_dev_alloc()中初始化dibs->lock |
| CVE-2026-74723 | 9.8 CRITICAL | btrfs LZO拒绝无有效头部的内联扩展 |
| CVE-2026-74730 | 9.8 CRITICAL | NFS：在FREE_STATEID调用期间锁定struct nfs_server |
| CVE-2026-74616 | 9.8 CRITICAL | Linux内核XDP克隆数据包越界漏洞 |
| CVE-2026-74727 | 9.8 CRITICAL | OpenVPN by_id移除后跳过哈希重构 |
| CVE-2026-74586 | 9.8 CRITICAL | Linux内核SCTP对等端移除时传输未清理漏洞 |
| CVE-2026-74611 | 9.8 CRITICAL | TLS 1.3 乐观重试消息迭代器恢复漏洞 |
| CVE-2026-74588 | 9.8 CRITICAL | Linux SCTP传输列表不同步漏洞 |
| CVE-2026-74712 | 9.3 CRITICAL | mlx5 vdpa 在 create_direct_keys() 中缓冲区长度修复漏洞 |
| CVE-2026-74665 | 9.1 CRITICAL | NET skb长度计算通用XDP片段调整后修复 |
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IV. Related Vulnerabilities
V. Comments for CVE-2026-74691
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