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CVE-2025-21925— llc: do not use skb_get() before dev_queue_xmit()

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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于在dev_queue_xmit前错误使用skb_get。

AI Predicted 7.8 Difficulty: Moderate EPSS 0.22% · P12

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< cd1c44327bbbd50fc24f2b38892f5f328b784d0f affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 13f3f872627f0f27c31245524fc11367756240ad affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 9b6f083db141ece0024be01526aa05aa978811cb affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 17f86e25431ebc15aa9245ff156414fdad47822d affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 416e8b4c20c6398044e93008deefd563289f477d affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 0f764208dc24ea043c3e20194d32aebf94f8459c affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 056e8a46d79e22983bae4267e0d9c52927076f46 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 64e6a754d33d31aa844b3ee66fb93ac84ca1565e affected
… +10 more rows
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I. Basic Information for CVE-2025-21925

Vulnerability Information
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Vulnerability Title
llc: do not use skb_get() before dev_queue_xmit()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: llc: do not use skb_get() before dev_queue_xmit() syzbot is able to crash hosts [1], using llc and devices not supporting IFF_TX_SKB_SHARING. In this case, e1000 driver calls eth_skb_pad(), while the skb is shared. Simply replace skb_get() by skb_clone() in net/llc/llc_s_ac.c Note that e1000 driver might have an issue with pktgen, because it does not clear IFF_TX_SKB_SHARING, this is an orthogonal change. We need to audit other skb_get() uses in net/llc. [1] kernel BUG at net/core/skbuff.c:2178 ! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:pskb_expand_head+0x6ce/0x1240 net/core/skbuff.c:2178 Call Trace: <TASK> __skb_pad+0x18a/0x610 net/core/skbuff.c:2466 __skb_put_padto include/linux/skbuff.h:3843 [inline] skb_put_padto include/linux/skbuff.h:3862 [inline] eth_skb_pad include/linux/etherdevice.h:656 [inline] e1000_xmit_frame+0x2d99/0x5800 drivers/net/ethernet/intel/e1000/e1000_main.c:3128 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3806 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:4045 [inline] __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4621 dev_queue_xmit include/linux/netdevice.h:3313 [inline] llc_sap_action_send_test_c+0x268/0x320 net/llc/llc_s_ac.c:144 llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline] llc_sap_next_state net/llc/llc_sap.c:182 [inline] llc_sap_state_process+0x239/0x510 net/llc/llc_sap.c:209 llc_ui_sendmsg+0xd0d/0x14e0 net/llc/af_llc.c:993 sock_sendmsg_nosec net/socket.c:718 [inline]
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
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于在dev_queue_xmit前错误使用skb_get。
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 ~ cd1c44327bbbd50fc24f2b38892f5f328b784d0f -
Linux Linux 2.6.12 -

II. Public POCs for CVE-2025-21925

# POC Description Source Link Shenlong Link
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III. Intelligence Information for CVE-2025-21925

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Patches & Fixes for CVE-2025-21925 (2)

Same Patch Batch · Linux · 2025-04-01 · 93 CVEs total

CVE-2025-21927 9.8 CRITICAL nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu()
CVE-2025-21954 9.8 CRITICAL netmem: prevent TX of unreadable skbs
CVE-2025-21969 8.8 HIGH Bluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd
CVE-2025-21955 8.8 HIGH ksmbd: prevent connection release during oplock break notification
CVE-2025-21972 8.8 HIGH net: mctp: unshare packets when reassembling
CVE-2025-21946 8.8 HIGH ksmbd: fix out-of-bounds in parse_sec_desc()
CVE-2025-21945 8.8 HIGH ksmbd: fix use-after-free in smb2_lock
CVE-2025-21967 8.8 HIGH ksmbd: fix use-after-free in ksmbd_free_work_struct
CVE-2025-21947 8.1 HIGH ksmbd: fix type confusion via race condition when using ipc_msg_send_request
CVE-2025-21934 7.8 HIGH rapidio: fix an API misues when rio_add_net() fails
CVE-2025-21923 7.8 HIGH HID: hid-steam: Fix use-after-free when detaching device
CVE-2025-21949 7.8 HIGH LoongArch: Set hugetlb mmap base address aligned with pmd size
CVE-2025-21919 7.8 HIGH sched/fair: Fix potential memory corruption in child_cfs_rq_on_list
CVE-2025-21914 7.8 HIGH slimbus: messaging: Free transaction ID in delayed interrupt scenario
CVE-2025-21924 7.8 HIGH net: hns3: make sure ptp clock is unregister and freed if hclge_ptp_get_cycle returns an e
CVE-2025-21958 7.8 HIGH Revert "openvswitch: switch to per-action label counting in conntrack"
CVE-2025-21965 7.8 HIGH sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()
CVE-2025-21926 7.8 HIGH net: gso: fix ownership in __udp_gso_segment
CVE-2025-21939 7.8 HIGH drm/xe/hmm: Don't dereference struct page pointers without notifier lock
CVE-2025-21985 7.8 HIGH drm/amd/display: Fix out-of-bound accesses

Showing top 20 of 93 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux