CVE-2026-31517 (GCVE-0-2026-31517)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:54 – Updated: 2026-05-11 22:10
VLAI?
Title
xfrm: iptfs: fix skb_put() panic on non-linear skb during reassembly
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix skb_put() panic on non-linear skb during reassembly In iptfs_reassem_cont(), IP-TFS attempts to append data to the new inner packet 'newskb' that is being reassembled. First a zero-copy approach is tried if it succeeds then newskb becomes non-linear. When a subsequent fragment in the same datagram does not meet the fast-path conditions, a memory copy is performed. It calls skb_put() to append the data and as newskb is non-linear it triggers SKB_LINEAR_ASSERT check. Oops: invalid opcode: 0000 [#1] SMP NOPTI [...] RIP: 0010:skb_put+0x3c/0x40 [...] Call Trace: <IRQ> iptfs_reassem_cont+0x1ab/0x5e0 [xfrm_iptfs] iptfs_input_ordered+0x2af/0x380 [xfrm_iptfs] iptfs_input+0x122/0x3e0 [xfrm_iptfs] xfrm_input+0x91e/0x1a50 xfrm4_esp_rcv+0x3a/0x110 ip_protocol_deliver_rcu+0x1d7/0x1f0 ip_local_deliver_finish+0xbe/0x1e0 __netif_receive_skb_core.constprop.0+0xb56/0x1120 __netif_receive_skb_list_core+0x133/0x2b0 netif_receive_skb_list_internal+0x1ff/0x3f0 napi_complete_done+0x81/0x220 virtnet_poll+0x9d6/0x116e [virtio_net] __napi_poll.constprop.0+0x2b/0x270 net_rx_action+0x162/0x360 handle_softirqs+0xdc/0x510 __irq_exit_rcu+0xe7/0x110 irq_exit_rcu+0xe/0x20 common_interrupt+0x85/0xa0 </IRQ> <TASK> Fix this by checking if the skb is non-linear. If it is, linearize it by calling skb_linearize(). As the initial allocation of newskb originally reserved enough tailroom for the entire reassembled packet we do not need to check if we have enough tailroom or extend it.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 , < 33a7b36268933c75bdc355e5531951e0ea9f1951 (git)
Affected: 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 , < 7fdfe8f6efeb0e1200e22a903f2471539f54522b (git)
Affected: 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 , < 0b352f83cabfefdaafa806d6471f0eca117dc7d5 (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "net/xfrm/xfrm_iptfs.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: fix skb_put() panic on non-linear skb during reassembly\n\nIn iptfs_reassem_cont(), IP-TFS attempts to append data to the new inner\npacket \u0027newskb\u0027 that is being reassembled. First a zero-copy approach is\ntried if it succeeds then newskb becomes non-linear.\n\nWhen a subsequent fragment in the same datagram does not meet the\nfast-path conditions, a memory copy is performed. It calls skb_put() to\nappend the data and as newskb is non-linear it triggers\nSKB_LINEAR_ASSERT check.\n\n Oops: invalid opcode: 0000 [#1] SMP NOPTI\n [...]\n RIP: 0010:skb_put+0x3c/0x40\n [...]\n Call Trace:\n  \u003cIRQ\u003e\n  iptfs_reassem_cont+0x1ab/0x5e0 [xfrm_iptfs]\n  iptfs_input_ordered+0x2af/0x380 [xfrm_iptfs]\n  iptfs_input+0x122/0x3e0 [xfrm_iptfs]\n  xfrm_input+0x91e/0x1a50\n  xfrm4_esp_rcv+0x3a/0x110\n  ip_protocol_deliver_rcu+0x1d7/0x1f0\n  ip_local_deliver_finish+0xbe/0x1e0\n  __netif_receive_skb_core.constprop.0+0xb56/0x1120\n  __netif_receive_skb_list_core+0x133/0x2b0\n  netif_receive_skb_list_internal+0x1ff/0x3f0\n  napi_complete_done+0x81/0x220\n  virtnet_poll+0x9d6/0x116e [virtio_net]\n  __napi_poll.constprop.0+0x2b/0x270\n  net_rx_action+0x162/0x360\n  handle_softirqs+0xdc/0x510\n  __irq_exit_rcu+0xe7/0x110\n  irq_exit_rcu+0xe/0x20\n  common_interrupt+0x85/0xa0\n  \u003c/IRQ\u003e\n  \u003cTASK\u003e\n\nFix this by checking if the skb is non-linear. If it is, linearize it by\ncalling skb_linearize(). As the initial allocation of newskb originally\nreserved enough tailroom for the entire reassembled packet we do not\nneed to check if we have enough tailroom or extend it."
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        "dateUpdated": "2026-05-11T22:10:19.646Z",
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    "dateReserved": "2026-03-09T15:48:24.108Z",
    "dateUpdated": "2026-05-11T22:10:19.646Z",
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  }
}


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