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CVE-2026-68136— net: gro: fix double aggregation of flush-marked skbs

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 5.6版本存在安全漏洞，该漏洞源于skb_gro_receive_list()缺少flush验证，可能导致已标记flush的报文被重新聚合，破坏frag_list链结构，触发内核崩溃。

CVSS 9.8 · Critical EPSS 0.54% · P44

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux 3a1296a38d0cf62bffb9a03c585cbd5dbf15d596< 7fc7e35212cf58c134310fb47566a844297ceae9 affected
3a1296a38d0cf62bffb9a03c585cbd5dbf15d596< d1fb23f8f794ac4683127bd49a6422bd87e0ac02 affected
3a1296a38d0cf62bffb9a03c585cbd5dbf15d596< db3e82da616f52e2b27e25e7be3fde2f2a5e54d6 affected
3a1296a38d0cf62bffb9a03c585cbd5dbf15d596< 107e1a469f53a2a70874f3f12bf6fcd23925da1d affected
3a1296a38d0cf62bffb9a03c585cbd5dbf15d596< a4dfd46cc8f08a29c6183794790547d0945f3d45 affected
3a1296a38d0cf62bffb9a03c585cbd5dbf15d596< fc0c0f7a207f0cd2d2aa725696c907f7d03af9e0 affected
3a1296a38d0cf62bffb9a03c585cbd5dbf15d596< e751256486d0ded20f5a9f9863467f1dce65142f affected
5.6 affected
… +8 more rows
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I. Basic Information for CVE-2026-68136

Vulnerability Information
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Vulnerability Title
net: gro: fix double aggregation of flush-marked skbs
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net: gro: fix double aggregation of flush-marked skbs Commit 0ab03f353d36 ("net-gro: Fix GRO flush when receiving a GSO packet.") added a flush check to skb_gro_receive(), but skb_gro_receive_list() lacks the same validation. As a result, packets marked with NAPI_GRO_CB(skb)->flush may still be re-aggregated. This allows already-GRO'd packets with existing frag_list to be re-aggregated into a new GRO session, corrupting the frag_list chain structure. When skb_segment() attempts to unpack these malformed packets, it encounters invalid state and triggers a kernel panic. Scenario (Tethering/Device forwarding): 1. Driver: Generated aggregated packet P1 via LRO with frag_list 2. Dev A: Receives aggregated fraglist packet and flush flag set 3. Dev A: Re-enters GRO, skb_gro_receive_list() is called 4. Missing flush check allows re-aggregation despite flush flag 5. Frag_list chain becomes corrupted (loops or dangling refs) 6. Dev B: TX path calls skb_segment(), crashes on corrupted frag_list Root cause in skb_segment(): The check at line ~4891: if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) && (skb_headlen(list_skb) == len || sg)) { When frag_list is corrupted by double aggregation, when list_skb is a NULL pointer from skb->next, skb_headlen(list_skb) dereference NULL/corrupted pointers occurs. Call Trace: skb_headlen(NULL skb) skb_segment tcp_gso_segment tcp4_gso_segment inet_gso_segment skb_mac_gso_segment __skb_gso_segment skb_gso_segment validate_xmit_skb validate_xmit_skb_list sch_direct_xmit qdisc_restart __qdisc_run qdisc_run net_tx_action Fix: Add NAPI_GRO_CB(skb)->flush validation to the early-return check in skb_gro_receive_list(), matching the defensive programming pattern of skb_gro_receive().
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/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 5.6版本存在安全漏洞，该漏洞源于skb_gro_receive_list()缺少flush验证，可能导致已标记flush的报文被重新聚合，破坏frag_list链结构，触发内核崩溃。
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 3a1296a38d0cf62bffb9a03c585cbd5dbf15d596 ~ 7fc7e35212cf58c134310fb47566a844297ceae9 -
Linux Linux 5.6 -

II. Public POCs for CVE-2026-68136

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III. Intelligence Information for CVE-2026-68136

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Patches & Fixes for CVE-2026-68136 (6)

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

CVE-2026-68117 9.8 CRITICAL tipc: clear sock->sk on the failed-insert path in tipc_sk_create()
CVE-2026-68160 9.8 CRITICAL ceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()
CVE-2026-68159 9.8 CRITICAL libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE
CVE-2026-68161 9.8 CRITICAL sctp: close UDP tunnel sockets during netns teardown
CVE-2026-68302 9.8 CRITICAL amt: re-read skb header pointers after every pull
CVE-2026-68158 9.8 CRITICAL libceph: Fix multiplication overflow in decode_new_up_state_weight()
CVE-2026-68123 9.8 CRITICAL openvswitch: fix GSO userspace truncation underflow
CVE-2026-68144 9.8 CRITICAL phonet: pep: fix use-after-free in pep_get_sb()
CVE-2026-68381 9.8 CRITICAL ksmbd: pin conn during async oplock break notification
CVE-2026-68385 9.8 CRITICAL s390/checksum: Fix csum_partial() without vector facility
CVE-2026-68154 9.8 CRITICAL libceph: reject zero bucket types in crush_decode
CVE-2026-68137 9.8 CRITICAL net/x25: fix use-after-free in x25_kill_by_neigh()
CVE-2026-68388 9.8 CRITICAL smb/client: handle overlapping allocated ranges in fallocate
CVE-2026-68426 9.8 CRITICAL xfrm: fix stale skb->prev after async crypto steals a GSO segment
CVE-2026-68300 9.8 CRITICAL sctp: auth: verify auth requirement when auth_chunk is NULL
CVE-2026-68127 9.8 CRITICAL ila: reload IPv6 header after pskb_may_pull in checksum adjust
CVE-2026-68170 9.8 CRITICAL mptcp: fix stale skb->sk reference on subflow close
CVE-2026-68156 9.8 CRITICAL libceph: refresh auth->authorizer_buf{,_len} after authorizer update
CVE-2026-68124 9.6 CRITICAL mctp: serial: handle zero-length frames to prevent rx buffer overflow
CVE-2026-68083 9.1 CRITICAL ksmbd: fix path resolution in ksmbd_vfs_kern_path_create

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

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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