CVE-2026-97612

Status: ReceivedHigh (7.8)—

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:

Read full descriptionShow less

so skb_network_offset() goes negative. The bound check is signed:

a negative offset passes it, and prepare_frag() widens the value:

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):

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.

Technical details traces, logs and code from the original report

	skb->network_header = skb->inner_network_header;

	if (skb_network_offset(skb) > MAX_L2_LEN)

	unsigned int hlen = skb_network_offset(skb);
	memcpy(&data->l2_data, skb->data, hlen);

  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

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 7.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.16%
Percentile among all scored CVEs: 5
Score date: 10/4/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1068 Exploitation for Privilege Escalationprivilege escalation60 %

Inferred by deterministic rules from the CVSS vector and CWE. Indicative only.

🛡️ ATT&CK mitigations that cover these techniques

Threat Intelligence Program Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux Kernel^AI

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-97612",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "lessThan": "55ed97db27bffe29c21fdefd5d25601322c36ff8",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "38db09804b2616aa1e2fcdf97f0c3ae8b9dbdd34",
              "versionType": "git"
            },
            {
              "status": "affected",
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              "status": "affected",
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              "lessThan": "011e17b5cae19b9f6a150923275e41c278de64f0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "48d2ab609b6bbecb7698487c8579bc40de9d6dfa",
              "lessThan": "da8c3a7f5d3137fec4ff60a6248f5f6d66b6a63e",
              "versionType": "git"
            },
            {
              "status": "affected",
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          ],
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.9"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.9",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-25T11:17:15.330",
  "references": [
    {
      "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",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "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->inner_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->eth.type and resets network_header, but leaves inner_*), then push\nagain. ovs_fragment() trusts the record:\n\n\tskb->network_header = skb->inner_network_header;\n\nso skb_network_offset() goes negative. The bound check is signed:\n\n\tif (skb_network_offset(skb) > 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(&data->l2_data, skb->data, 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."
    }
  ],
  "lastModified": "2026-10-03T11:18:07.643",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}