CVE-2026-46306 (GCVE-0-2026-46306)

Vulnerability from cvelistv5 – Published: 2026-06-08 15:46 – Updated: 2026-06-14 18:08
VLAI
Title
flow_dissector: do not dissect PPPoE PFC frames
Summary
In the Linux kernel, the following vulnerability has been resolved: flow_dissector: do not dissect PPPoE PFC frames RFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT RECOMMENDED for PPPoE. In practice, pppd does not support negotiating PFC for PPPoE sessions, and the flow dissector driver has assumed an uncompressed frame until the blamed commit. During the review process of that commit [1], support for PFC is suggested. However, having a compressed (1-byte) protocol field means the subsequent PPP payload is shifted by one byte, causing 4-byte misalignment for the network header and an unaligned access exception on some architectures. The exception can be reproduced by sending a PPPoE PFC frame to an ethernet interface of a MIPS board, with RPS enabled, even if no PPPoE session is active on that interface: $ 0 : 00000000 80c40000 00000000 85144817 $ 4 : 00000008 00000100 80a75758 81dc9bb8 $ 8 : 00000010 8087ae2c 0000003d 00000000 $12 : 000000e0 00000039 00000000 00000000 $16 : 85043240 80a75758 81dc9bb8 00006488 $20 : 0000002f 00000007 85144810 80a70000 $24 : 81d1bda0 00000000 $28 : 81dc8000 81dc9aa8 00000000 805ead08 Hi : 00009d51 Lo : 2163358a epc : 805e91f0 __skb_flow_dissect+0x1b0/0x1b50 ra : 805ead08 __skb_get_hash_net+0x74/0x12c Status: 11000403 KERNEL EXL IE Cause : 40800010 (ExcCode 04) BadVA : 85144817 PrId : 0001992f (MIPS 1004Kc) Call Trace: [<805e91f0>] __skb_flow_dissect+0x1b0/0x1b50 [<805ead08>] __skb_get_hash_net+0x74/0x12c [<805ef330>] get_rps_cpu+0x1b8/0x3fc [<805fca70>] netif_receive_skb_list_internal+0x324/0x364 [<805fd120>] napi_complete_done+0x68/0x2a4 [<8058de5c>] mtk_napi_rx+0x228/0xfec [<805fd398>] __napi_poll+0x3c/0x1c4 [<805fd754>] napi_threaded_poll_loop+0x234/0x29c [<805fd848>] napi_threaded_poll+0x8c/0xb0 [<80053544>] kthread+0x104/0x12c [<80002bd8>] ret_from_kernel_thread+0x14/0x1c Code: 02d51821 1060045b 00000000 <8c640000> 3084000f 2c820005 144001a2 00042080 8e220000 To reduce the attack surface and maintain performance, do not process PPPoE PFC frames. [1] https://lore.kernel.org/r/20220630231016.GA392@debian.home
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 10f665b52a75df6eb26ddebbbc072ee264183731 , < e7c811ca372d53c2be7d01a1614e71fae1054836 (git)
Affected: d7e541e86122d21f71eb71c5dfa7fb1eb6623fe8 , < abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200 (git)
Affected: 46126db9c86110e5fc1e369b9bb89735ddefdae4 , < 18ae9eacfc95cc715c0606b2c86e8aa8a86cf3e3 (git)
Affected: 46126db9c86110e5fc1e369b9bb89735ddefdae4 , < db104b0d8a7856397c0469d83a4289adf7c54863 (git)
Affected: 46126db9c86110e5fc1e369b9bb89735ddefdae4 , < 6044392d9cace3a3672b02c8bc7d38b502e51734 (git)
Affected: 46126db9c86110e5fc1e369b9bb89735ddefdae4 , < 0d00b9015069712944934bab09eaa6c542143049 (git)
Affected: 46126db9c86110e5fc1e369b9bb89735ddefdae4 , < 7c93f353eab4ea911e394630f07d72e040a729d8 (git)
Affected: 46126db9c86110e5fc1e369b9bb89735ddefdae4 , < d6c19b31a3c1d519fabdcf0aa239e6b6109b9473 (git)
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Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.1.175 , ≤ 6.1.* (semver)
Unaffected: 6.6.140 , ≤ 6.6.* (semver)
Unaffected: 6.12.88 , ≤ 6.12.* (semver)
Unaffected: 6.18.30 , ≤ 6.18.* (semver)
Unaffected: 7.0.7 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.6.140",
              "versionType": "semver"
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              "status": "unaffected",
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              "versionType": "semver"
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              "status": "unaffected",
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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          "nodes": [
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                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nflow_dissector: do not dissect PPPoE PFC frames\n\nRFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT\nRECOMMENDED for PPPoE. In practice, pppd does not support negotiating\nPFC for PPPoE sessions, and the flow dissector driver has assumed an\nuncompressed frame until the blamed commit.\n\nDuring the review process of that commit [1], support for PFC is\nsuggested. However, having a compressed (1-byte) protocol field means\nthe subsequent PPP payload is shifted by one byte, causing 4-byte\nmisalignment for the network header and an unaligned access exception\non some architectures.\n\nThe exception can be reproduced by sending a PPPoE PFC frame to an\nethernet interface of a MIPS board, with RPS enabled, even if no PPPoE\nsession is active on that interface:\n\n$ 0   : 00000000 80c40000 00000000 85144817\n$ 4   : 00000008 00000100 80a75758 81dc9bb8\n$ 8   : 00000010 8087ae2c 0000003d 00000000\n$12   : 000000e0 00000039 00000000 00000000\n$16   : 85043240 80a75758 81dc9bb8 00006488\n$20   : 0000002f 00000007 85144810 80a70000\n$24   : 81d1bda0 00000000\n$28   : 81dc8000 81dc9aa8 00000000 805ead08\nHi    : 00009d51\nLo    : 2163358a\nepc   : 805e91f0 __skb_flow_dissect+0x1b0/0x1b50\nra    : 805ead08 __skb_get_hash_net+0x74/0x12c\nStatus: 11000403        KERNEL EXL IE\nCause : 40800010 (ExcCode 04)\nBadVA : 85144817\nPrId  : 0001992f (MIPS 1004Kc)\nCall Trace:\n[\u003c805e91f0\u003e] __skb_flow_dissect+0x1b0/0x1b50\n[\u003c805ead08\u003e] __skb_get_hash_net+0x74/0x12c\n[\u003c805ef330\u003e] get_rps_cpu+0x1b8/0x3fc\n[\u003c805fca70\u003e] netif_receive_skb_list_internal+0x324/0x364\n[\u003c805fd120\u003e] napi_complete_done+0x68/0x2a4\n[\u003c8058de5c\u003e] mtk_napi_rx+0x228/0xfec\n[\u003c805fd398\u003e] __napi_poll+0x3c/0x1c4\n[\u003c805fd754\u003e] napi_threaded_poll_loop+0x234/0x29c\n[\u003c805fd848\u003e] napi_threaded_poll+0x8c/0xb0\n[\u003c80053544\u003e] kthread+0x104/0x12c\n[\u003c80002bd8\u003e] ret_from_kernel_thread+0x14/0x1c\n\nCode: 02d51821  1060045b  00000000 \u003c8c640000\u003e 3084000f  2c820005  144001a2  00042080  8e220000\n\nTo reduce the attack surface and maintain performance, do not process\nPPPoE PFC frames.\n\n[1] https://lore.kernel.org/r/20220630231016.GA392@debian.home"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
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      "providerMetadata": {
        "dateUpdated": "2026-06-14T18:08:00.552Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/e7c811ca372d53c2be7d01a1614e71fae1054836"
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        {
          "url": "https://git.kernel.org/stable/c/abc5bc84e0f2edc7ea2d437afa6ef3fe1fc43200"
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          "url": "https://git.kernel.org/stable/c/d6c19b31a3c1d519fabdcf0aa239e6b6109b9473"
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      ],
      "title": "flow_dissector: do not dissect PPPoE PFC frames",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46306",
    "datePublished": "2026-06-08T15:46:33.936Z",
    "dateReserved": "2026-05-13T15:03:33.111Z",
    "dateUpdated": "2026-06-14T18:08:00.552Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-46306",
      "date": "2026-06-24",
      "epss": "0.00389",
      "percentile": "0.30609"
    },
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.