FKIE_CVE-2026-97612

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-10-19 10:17
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: mpls: clear inner_protocol when the last label is popped skb_mpls_push() records the pre-encapsulation network header once, gated on !skb->inner_protocol. skb_mpls_pop() never clears that record, so it outlives the encapsulation it describes. Open vSwitch can then re-push MPLS onto a packet whose inner_network_header still points at the older, deeper offset: push a label, pop every label, recirculate (ovs_flow_key_update() re-derives key->eth.type and resets network_header, but leaves inner_*), then push again. ovs_fragment() trusts the record: skb->network_header = skb->inner_network_header; so skb_network_offset() goes negative. The bound check is signed: if (skb_network_offset(skb) > MAX_L2_LEN) a negative offset passes it, and prepare_frag() widens the value: unsigned int hlen = skb_network_offset(skb); memcpy(&data->l2_data, skb->data, hlen); which is a ~4GiB memcpy out of a 30-byte per-CPU buffer. Reproduced on v7.3-rc1. RDX is the truncated length, (unsigned int)(-8): BUG: unable to handle page fault for address: ffffe8ffffc16000 #PF: supervisor write access in kernel mode Oops: 0002 [#1] SMP KASAN NOPTI RIP: 0010:memcpy+0x8/0x20 RDX: 00000000fffffff8 RSI: ffff888105d732db RDI: ffffe8ffffc16000 prepare_frag+0x3df/0x4e0 ovs_fragment+0x589/0x7e0 do_output+0x4ce/0x5e0 do_execute_actions+0x55d2/0x7b30 ovs_execute_actions+0xea/0x450 Same root-cause shape as commit 975b5b067f52 ("ipv6: sr: restore network header before routing and forwarding"): a stale network header offset reaching a consumer that widens it. Here it originates in the MPLS push/pop path. Clear inner_protocol once the packet is no longer MPLS, so a later push re-records the current header. net/sched/act_mpls.c is the only other skb_mpls_pop() caller and gets the same fix; sch_frag.c saves and restores inner_protocol around fragmentation in the same way OVS does.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/011e17b5cae19b9f6a150923275e41c278de64f0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0b3425fd0ecd515997956f7bb8a8a576b444ed64
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/38db09804b2616aa1e2fcdf97f0c3ae8b9dbdd34
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/55ed97db27bffe29c21fdefd5d25601322c36ff8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/78a86d75a70e1e227711c72865c59b1422d0a5ae
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/833ec2788322306407503b4cfc7745cd1f9d785f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b39120523475d6b436be7f6cb27d48064148a327
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/da8c3a7f5d3137fec4ff60a6248f5f6d66b6a63e
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "55ed97db27bffe29c21fdefd5d25601322c36ff8",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            },
            {
              "lessThan": "833ec2788322306407503b4cfc7745cd1f9d785f",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            },
            {
              "lessThan": "38db09804b2616aa1e2fcdf97f0c3ae8b9dbdd34",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            },
            {
              "lessThan": "0b3425fd0ecd515997956f7bb8a8a576b444ed64",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            },
            {
              "lessThan": "011e17b5cae19b9f6a150923275e41c278de64f0",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            },
            {
              "lessThan": "da8c3a7f5d3137fec4ff60a6248f5f6d66b6a63e",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            },
            {
              "lessThan": "b39120523475d6b436be7f6cb27d48064148a327",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            },
            {
              "lessThan": "78a86d75a70e1e227711c72865c59b1422d0a5ae",
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.9"
            },
            {
              "lessThan": "4.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mpls: clear inner_protocol when the last label is popped\n\nskb_mpls_push() records the pre-encapsulation network header once, gated\non !skb-\u003einner_protocol. skb_mpls_pop() never clears that record, so it\noutlives the encapsulation it describes.\n\nOpen vSwitch can then re-push MPLS onto a packet whose\ninner_network_header still points at the older, deeper offset: push a\nlabel, pop every label, recirculate (ovs_flow_key_update() re-derives\nkey-\u003eeth.type and resets network_header, but leaves inner_*), then push\nagain. ovs_fragment() trusts the record:\n\n\tskb-\u003enetwork_header = skb-\u003einner_network_header;\n\nso skb_network_offset() goes negative. The bound check is signed:\n\n\tif (skb_network_offset(skb) \u003e MAX_L2_LEN)\n\na negative offset passes it, and prepare_frag() widens the value:\n\n\tunsigned int hlen = skb_network_offset(skb);\n\tmemcpy(\u0026data-\u003el2_data, skb-\u003edata, hlen);\n\nwhich is a ~4GiB memcpy out of a 30-byte per-CPU buffer.\n\nReproduced on v7.3-rc1. RDX is the truncated length, (unsigned int)(-8):\n\n  BUG: unable to handle page fault for address: ffffe8ffffc16000\n  #PF: supervisor write access in kernel mode\n  Oops: 0002 [#1] SMP KASAN NOPTI\n  RIP: 0010:memcpy+0x8/0x20\n  RDX: 00000000fffffff8 RSI: ffff888105d732db RDI: ffffe8ffffc16000\n   prepare_frag+0x3df/0x4e0\n   ovs_fragment+0x589/0x7e0\n   do_output+0x4ce/0x5e0\n   do_execute_actions+0x55d2/0x7b30\n   ovs_execute_actions+0xea/0x450\n\nSame root-cause shape as commit 975b5b067f52 (\"ipv6: sr: restore network\nheader before routing and forwarding\"): a stale network header offset\nreaching a consumer that widens it. Here it originates in the MPLS\npush/pop path.\n\nClear inner_protocol once the packet is no longer MPLS, so a later push\nre-records the current header. net/sched/act_mpls.c is the only other\nskb_mpls_pop() caller and gets the same fix; sch_frag.c saves and\nrestores inner_protocol around fragmentation in the same way OVS does."
    }
  ],
  "id": "CVE-2026-97612",
  "lastModified": "2026-10-19T10:17:31.307",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-25T11:17:15.330",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/011e17b5cae19b9f6a150923275e41c278de64f0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0b3425fd0ecd515997956f7bb8a8a576b444ed64"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/38db09804b2616aa1e2fcdf97f0c3ae8b9dbdd34"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/55ed97db27bffe29c21fdefd5d25601322c36ff8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/78a86d75a70e1e227711c72865c59b1422d0a5ae"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/833ec2788322306407503b4cfc7745cd1f9d785f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b39120523475d6b436be7f6cb27d48064148a327"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/da8c3a7f5d3137fec4ff60a6248f5f6d66b6a63e"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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