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CVE-2026-68121— pppoe: reload header pointer after dev_hard_header()

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基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于pppoe_sendmsg()在调用dev_hard_header()后未重新加载PPPoE头指针，导致释放后重用，可能造成内存破坏。

CVSS 7.8 · High EPSS 0.30% · P21

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 6eed5ae7887a93160803d2b81ff88e75eefd4a4c affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< ba3409369c5413cdf0dcbf3a928f76b48e8c3e6a affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< e6493a4d1ee17595766165fa446d45b7e0c318d0 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 7e9fbd7f96bcde63a7c798fe16b38cedee7a1501 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 6866abf59976d273164a6624234d96a967280223 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< bed4caecd723693f750e13adbb2c42ca1249a3fd affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< e9c238f6fe42fb1b4dba3a578277de32cb487937 affected
… +10 more rows
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I. Basic Information for CVE-2026-68121

Vulnerability Information
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Vulnerability Title
pppoe: reload header pointer after dev_hard_header()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: pppoe: reload header pointer after dev_hard_header() pppoe_sendmsg() saves a pointer to the PPPoE header before calling dev_hard_header(). Device header callbacks are allowed to reallocate the skb head, invalidating pointers into it. This can happen when a send is blocked in copy_from_user() while the first non-Ethernet port is added to an empty team device. The team's delegated GRE header callback then expands the skb head. PPPoE subsequently writes six bytes through the stale pointer into the freed head. Reload the PPPoE header through the skb's network-header offset after device header creation. pskb_expand_head() updates that offset when it relocates the head.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于pppoe_sendmsg()在调用dev_hard_header()后未重新加载PPPoE头指针，导致释放后重用，可能造成内存破坏。
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 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ~ 7a56e7c9b08e08fd55a1bcada24cf4fe3782b722 -
Linux Linux 2.6.12 -

II. Public POCs for CVE-2026-68121

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III. Intelligence Information for CVE-2026-68121

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Patches & Fixes for CVE-2026-68121 (8)

Same Patch Batch · Linux · 2026-08-10 · 344 CVEs total

CVE-2026-68136 9.8 CRITICAL net: gro: fix double aggregation of flush-marked skbs
CVE-2026-68144 9.8 CRITICAL phonet: pep: fix use-after-free in pep_get_sb()
CVE-2026-68127 9.8 CRITICAL ila: reload IPv6 header after pskb_may_pull in checksum adjust
CVE-2026-68302 9.8 CRITICAL amt: re-read skb header pointers after every pull
CVE-2026-68154 9.8 CRITICAL libceph: reject zero bucket types in crush_decode
CVE-2026-68156 9.8 CRITICAL libceph: refresh auth->authorizer_buf{,_len} after authorizer update
CVE-2026-68158 9.8 CRITICAL libceph: Fix multiplication overflow in decode_new_up_state_weight()
CVE-2026-68159 9.8 CRITICAL libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE
CVE-2026-68160 9.8 CRITICAL ceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()
CVE-2026-68300 9.8 CRITICAL sctp: auth: verify auth requirement when auth_chunk is NULL
CVE-2026-68161 9.8 CRITICAL sctp: close UDP tunnel sockets during netns teardown
CVE-2026-68117 9.8 CRITICAL tipc: clear sock->sk on the failed-insert path in tipc_sk_create()
CVE-2026-68388 9.8 CRITICAL smb/client: handle overlapping allocated ranges in fallocate
CVE-2026-68137 9.8 CRITICAL net/x25: fix use-after-free in x25_kill_by_neigh()
CVE-2026-68426 9.8 CRITICAL xfrm: fix stale skb->prev after async crypto steals a GSO segment
CVE-2026-68385 9.8 CRITICAL s390/checksum: Fix csum_partial() without vector facility
CVE-2026-68123 9.8 CRITICAL openvswitch: fix GSO userspace truncation underflow
CVE-2026-68381 9.8 CRITICAL ksmbd: pin conn during async oplock break notification
CVE-2026-68170 9.8 CRITICAL mptcp: fix stale skb->sk reference on subflow close
CVE-2026-68124 9.6 CRITICAL mctp: serial: handle zero-length frames to prevent rx buffer overflow

Showing top 20 of 344 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-68121

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