CVE-2026-98158— Linux ppp_async 丢弃错误帧而非重置其头部空间漏洞
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，已修复以下漏洞： ppp_async：丢弃出错帧，而不是重置其 headroom（头部预留空间） 在运行 pass/active BPF 过滤器之前，会在 skb 前 prepends（前置）一个两字节的方向标签： 在接收路径上，没有任何内容能保证这两个字节的 headroom 存在。 中 的帧错误处理路径会将被重用的 skb 的 headroom 重置为零，同时声称将其恢复到全新分配的状态——但实际上，从 获取的新 skb 会携带 预留空间： 仍指向该 skb，因此下一帧将被重新组装到其中
可能的 ATT&CK 技术 1 AI
T1498 · Network Denial of Service影响版本矩阵 18
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | 6722e78c90054101e6797d5944cdc81af9897a0a< 25f354c55b8435d1f51b8a0a05a3cfe429358523 |
affected |
6722e78c90054101e6797d5944cdc81af9897a0a< a86a17745c3e1c6fadd4d6e90c03552dfe531c8c |
affected | ||
6722e78c90054101e6797d5944cdc81af9897a0a< ff035780adb0f49dc2c7ada26b4697849a68bec8 |
affected | ||
6722e78c90054101e6797d5944cdc81af9897a0a< c4bb894362d224b699e2f95c6c26707d9654e4a3 |
affected | ||
6722e78c90054101e6797d5944cdc81af9897a0a< d0fc3dabfe67caf084e7119ceb2ee23f5ad2f2da |
affected | ||
6722e78c90054101e6797d5944cdc81af9897a0a< 0c53eb14975f029abd6b26896a460f0d2aaefe6b |
affected | ||
6722e78c90054101e6797d5944cdc81af9897a0a< 717137221c7d90e7c98bda9a370c9da6cbf015e5 |
affected | ||
6722e78c90054101e6797d5944cdc81af9897a0a< 8dc5d98a16fa23c00999aecf10018c9f69fa5bf4 |
affected | ||
| … +10 条更多 | |||
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一、 漏洞 CVE-2026-98158 基础信息
漏洞信息
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Vulnerability Title
ppp_async: drop the errored frame instead of resetting its headroom
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
ppp_async: drop the errored frame instead of resetting its headroom
ppp_receive_nonmp_frame() prepends a two-byte direction tag before running
the pass/active BPF filters:
*(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_INBOUND_TAG);
Nothing on the receive path guarantees those two bytes of headroom. The
frame-error path in ppp_async's process_input_packet() resets a reused skb's
headroom to zero while claiming to restore it to a freshly allocated state -
but a fresh skb from dev_alloc_skb() carries NET_SKB_PAD:
err:
if (skb) {
/* make skb appear as freshly allocated */
skb_trim(skb, 0);
skb_reserve(skb, - skb_headroom(skb));
}
ap->rpkt still points at that skb, so the next frame is reassembled into it
with no headroom at all. A peer that sends a bad-FCS frame followed by one
beginning ff 03 then leaves a single byte of headroom by the time the filter
tag is pushed, which lands one byte below skb->head:
skbuff: skb_under_panic: len:49 put:2 head:ffff888003c10000
data:ffff888003c0ffff tail:0x30 end:0x640 dev:<NULL>
kernel BUG at net/core/skbuff.c:214!
RIP: 0010:skb_panic+0x13e/0x230
Call Trace:
skb_push+0xbd/0x100
ppp_receive_nonmp_frame+0x48a/0x1d10
ppp_input+0x4e9/0x2f80
ppp_async_process+0x2a/0xe0
tasklet_action_common+0x20f/0x8a0
handle_softirqs+0x18e/0x590
Kernel panic - not syncing: Fatal exception in interrupt
Zeroing the headroom violates the NET_SKB_PAD guarantee that dev_alloc_skb()
gives the rest of the receive path. Besides the filter panic above, when CCP
compression is enabled ppp_decompress_frame() hands skb->data - 2 to
->decompress()/->incomp(), which then reads out of bounds before skb->head
for the same reason.
Rather than restore the headroom, drop the errored frame - as ppp_synctty
already does on its error path - and clear ap->rpkt so the next frame is
reassembled into a fresh skb with proper headroom. This is simpler and fixes
both the filter under-panic and the CCP out-of-bounds read.
The original V1 of this patch made room in ppp_receive_nonmp_frame() with
skb_cow_head(); Eric pointed out that fixing the root cause in the transport
is the right approach.
Found by fuzzing the PPP receive path with a mutating peer on a pty; it is an
interesting (remote) DoS: root configures PPP, the peer supplies two crashing
frames. The reproducer (repro-ppp-skb.c, unchanged from v1) panics in about a
second, and returns cleanly with this applied.
来源: CVE Program / CVE List V5
CVSS Information
N/A
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-2026-98158 的公开POC
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|---|
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CVE-2026-98158 补丁与修复 (8)
同批安全公告 · Linux · 2026-09-25 · 共 372 条
| CVE-2026-100075 | 9.8 CRITICAL | RDMA/srpt：srpt_alloc_rw_ctxs() 未释放计数器修复 |
| CVE-2026-97555 | 8.8 HIGH | smb客户端：修复DACL所有者/组重写中的堆溢出漏洞 |
| CVE-2026-97957 | 8.8 HIGH | hinic 邮箱段缓冲区溢出漏洞 |
| CVE-2026-97527 | 8.8 HIGH | qla2xxx SCSI驱动程序 NVMe未解决上下文列表竞争条件漏洞 |
| CVE-2026-97528 | 8.8 HIGH | QLogic qla2xxx驱动LS拒绝错误NVMe内存泄漏漏洞 |
| CVE-2026-98115 | 8.8 HIGH | ksmbd 注销期间会话安全排空漏洞 |
| CVE-2026-97525 | 8.2 HIGH | x86/mm/pat：内核页表分裂页表分配漏洞 |
| CVE-2026-98069 | 8.1 HIGH | Net/RDS rds_conn_shutdown() 快速路径锁获取漏洞 |
| CVE-2026-97573 | 8.1 HIGH | bnxt_en 驱动 bnxt_rx_ring_reset 缓冲区分配失败漏洞 |
| CVE-2026-97570 | 8.1 HIGH | bnxt_en: 修复因SW TPA ID绑定问题导致的崩溃漏洞 |
| CVE-2026-98130 | 8.1 HIGH | SCTP定时器启动竞争条件漏洞 |
| CVE-2026-98070 | 8.1 HIGH | Linux RDS 模块远程代码执行漏洞 |
| CVE-2026-98122 | 7.8 HIGH | Linux内核vxlan mdb远程源删除后使用漏洞 |
| CVE-2026-97575 | 7.8 HIGH | v4l2-ctrls AV1瓦片计数验证漏洞 |
| CVE-2026-97576 | 7.8 HIGH | V4L2-ctrls HEVC 瓦片计数验证漏洞 |
| CVE-2026-97941 | 7.8 HIGH | Linux 内核 slab 内存分配器竞态条件漏洞 |
| CVE-2026-98112 | 7.8 HIGH | ksmbd 网络接口事件中监听器任务生命周期修复漏洞 |
| CVE-2026-98116 | 7.8 HIGH | ALSA: PCM内存映射与缓冲区重新分配序列化以修复页面UAF漏洞 |
| CVE-2026-97580 | 7.8 HIGH | rkvdec HEVC解析数组越界漏洞 |
| CVE-2026-97940 | 7.8 HIGH | IPv6 修复 fib6 遍历器在 seq 停止时存在 UAF 漏洞 |
显示前 20 条，共 372 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-98158
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