CVE-2026-98570— net: ipv6: keep room for the mac header in dst_dev_overhead()
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.
在 Linux 内核中，以下漏洞已被修复： net: ipv6: 在 dst_dev_overhead() 中为 MAC 头部预留空间 seg6、ioam6 和 rpl 的 LWTunnel 在调用 时，会将请求长度设置为即将推送的头部长度加上 的返回值，随后推送新头部，并通过 在其下方重建 MAC 头部。该重建操作需要 大小的头部预留空间（headroom），但 仅返回出接口的 （对于普通以太网为 16 字节）。 当 MAC 头部长度超过该预留空间时（例如，在 关闭的情况下，通过 VLAN 设备入站），重建过程会
Possible ATT&CK Techniques 1 AI
T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-98570
Vulnerability Information
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Vulnerability Title
net: ipv6: keep room for the mac header in dst_dev_overhead()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: keep room for the mac header in dst_dev_overhead()
The seg6, ioam6 and rpl lwtunnels size their skb_cow_head() request as
the length they are about to push plus dst_dev_overhead(), then push the
new headers and rebuild the mac header below them with
skb_mac_header_rebuild(). That rebuild needs skb->mac_len of headroom,
but dst_dev_overhead() leaves LL_RESERVED_SPACE() of the egress device,
16 bytes for plain Ethernet.
Where the mac header is longer than that, as it is on ingress through a
VLAN device with reorder_hdr off, the rebuild runs out of room:
skb_set_mac_header(skb, -skb->mac_len) computes a negative offset,
stores it unchecked in the u16 skb->mac_header, and the memmove that
follows writes skb->mac_len bytes about 64 KB past skb->head.
Forwarding plain ping6 traffic through such a device reproduces it on
all five seg6 encapsulation modes and on the rpl and ioam6 inline paths;
skb->mac_header comes back as 65534 on a 704-byte head.
Return the larger of the two. The helper already returns skb->mac_len
when it has no dst, so this only makes the other branch agree, and it
covers every caller rather than each call site in turn.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-98570
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Other References for CVE-2026-98570 (2)
Same Patch Batch · Linux · 2026-10-18 · 436 CVEs total
| CVE-2026-98583 | nfc: nfcmrvl: validate helper command length before pull | |
| CVE-2026-98568 | vxlan: use one headroom snapshot for neighbour replies | |
| CVE-2026-98571 | net: stmmac: clear stale buf->page after recycling on skb build failure | |
| CVE-2026-98572 | bpf: Fix immediate JMP JEQ/JNE on MIPS32 | |
| CVE-2026-98573 | net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6() | |
| CVE-2026-98574 | net: bcmgenet: stop Tx NAPI before disabling the queues | |
| CVE-2026-98575 | nfc: pn533: fix OOB read in pn533_acr122_is_rx_frame_valid() | |
| CVE-2026-98576 | nfc: llcp: fix slab-out-of-bounds reads when logging service names | |
| CVE-2026-98577 | nfc: llcp: fix WKS SAP hijacking via prefix match in nfc_llcp_wks_sap() | |
| CVE-2026-98578 | nfc: st21nfca: validate ISO15693 inventory length | |
| CVE-2026-98579 | nfc: llcp: fix sdreq TLV list leak on parse/alloc/send failure | |
| CVE-2026-98580 | nfc: llcp: Fix race condition in accept_queue lifecycle | |
| CVE-2026-98581 | nfc: llcp: Fix list corruption / refcount desync in nfc_llcp_recv_dm() | |
| CVE-2026-98582 | nfc: st21nfca: validate received frame size | |
| CVE-2026-98594 | tg3: clean up PHYLIB resources on probe failure | |
| CVE-2026-98591 | bpf: Fix bounds check for skb-backed dynptrs | |
| CVE-2026-98592 | net: spacemit: clear TX descriptor on fragment mapping failure | |
| CVE-2026-98593 | s390/debug: Fix NULL pointer dereference in debug_info_copy() | |
| CVE-2026-98590 | bpf: Fix bpf_sock context code generation | |
| CVE-2026-98595 | udp: remove a disconnected socket from the 4-tuple hash table |
Showing top 20 of 436 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
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CVE-2026-98868
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sched/cache: Introduce task_struct->sched_cache_grp to fix U -
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CVE-2026-98864
sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing
Same vendor: Linux
-
CVE-2026-98868
dm-pcache: reject a kset that overruns its segment -
CVE-2026-98867
dm-pcache: bound the logical key offset from persistent memo -
CVE-2026-98866
sched/cache: Introduce task_struct->sched_cache_grp to fix U -
CVE-2026-98865
sched_ext: Don't run ops.dequeue() with a DSQ lock held -
CVE-2026-98864
sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing
V. Comments for CVE-2026-98570
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