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CVE-2026-90059

Estado: RecibidaAlta (7.5)—

In the Linux kernel, the following vulnerability has been resolved:

net: stmmac: restore NET_IP_ALIGN in the RX DMA offset

Since the RX path was converted to zero-copy, the page pool page is handed to the stack directly as the skb head, and the offset the DMA engine writes at is what determines the alignment of the packet headers.

Before the conversion the payload was copied into an skb obtained from napi_alloc_skb(), which reserves NET_SKB_PAD + NET_IP_ALIGN. The conversion moved the headroom into stmmac_rx_offset() but did not carry over NET_IP_ALIGN, so on architectures where NET_IP_ALIGN is 2 the IP header now lands misaligned:

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Same for the XDP branch:

On ARM32 this is fatal, because ldm and ldrd trap on unaligned addresses even when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set.

Any received echo request panics the machine, e.g:

The faulting instruction is the ldm of *icmp_hdr(skb) in icmp_echo().

Fix by adding NET_IP_ALIGN back to the RX offset, which restores the alignment the stack used to get.

Note that commit a955318fe67e ("stmmac: align RX buffers") made a similar change in 2021 and was reverted by commit 12d125b4574b ("stmmac: Revert "stmmac: align RX buffers"") because it caused packet corruption. That patch raised the offset from 0 without adjusting the buffer size accounting, so the DMA engine could arguably write past the end of the RX buffers, though this was never root caused. Commit df542f669307 ("net: stmmac: Switch to zero-copy in non-XDP RX path") since derives the page pool allocation from stmmac_rx_offset(), so the extra bytes are accounted for.

Detalles técnicos trazas, registros y código del informe original
  64 (NET_SKB_PAD) + 14 (ethernet) + 20 (IP) = 98

  256 (XDP_PACKET_HEADROOM) + 14 (ethernet) + 20 (IP) = 290

  Unhandled fault: alignment exception (0x001) at 0x81873062
  Internal error: : 1 [#1] SMP ARM
  Hardware name: Altera SOCFPGA Arria10
  PC is at icmp_echo+0x38/0xa8
  LR is at icmp_rcv+0x22c/0x370
  Call trace:
   icmp_echo from icmp_rcv+0x22c/0x370
   icmp_rcv from ip_protocol_deliver_rcu+0x2c/0x224
   ip_protocol_deliver_rcu from ip_local_deliver+0xc8/0x1a0
   ip_local_deliver from ip_sublist_rcv_finish+0x3c/0x50
   ip_sublist_rcv_finish from ip_list_rcv_finish+0x110/0x118
   ip_list_rcv_finish from ip_list_rcv+0xc8/0xdc
   ip_list_rcv from __netif_receive_skb_list_core+0x170/0x1c0
   ...
   napi_complete_done from stmmac_napi_poll_rx+0xcb0/0x1030
  Code: e24dd068 e59020a0 e28dc010 e0822001 (e8920003)
  Kernel panic - not syncing: Fatal exception in interrupt

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad en el kernel de Linux (AV:N) que causa panic del sistema al procesar paquetes ICMP mal alineados, resultando en DoS remoto sin autenticación ni interacción.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-90059",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "df542f669307918f054a17878ff6dd1ddbb2fe18",
              "lessThan": "2ea42936416b29cca42b2c7bc7d3d3768f77c199",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "df542f669307918f054a17878ff6dd1ddbb2fe18",
              "lessThan": "c0d3f9560cc890bc2d96d9f487584688ae6e5185",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "df542f669307918f054a17878ff6dd1ddbb2fe18",
              "lessThan": "23680bf5f8c69c923546b84a8e6c401bef8b88fe",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.14",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/net/ethernet/stmicro/stmmac/stmmac_main.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-17T17:16:54.590",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/23680bf5f8c69c923546b84a8e6c401bef8b88fe",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2ea42936416b29cca42b2c7bc7d3d3768f77c199",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c0d3f9560cc890bc2d96d9f487584688ae6e5185",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: restore NET_IP_ALIGN in the RX DMA offset\n\nSince the RX path was converted to zero-copy, the page pool page is handed\nto the stack directly as the skb head, and the offset the DMA engine writes\nat is what determines the alignment of the packet headers.\n\nBefore the conversion the payload was copied into an skb obtained from\nnapi_alloc_skb(), which reserves NET_SKB_PAD + NET_IP_ALIGN. The\nconversion moved the headroom into stmmac_rx_offset() but did not carry\nover NET_IP_ALIGN, so on architectures where NET_IP_ALIGN is 2 the IP\nheader now lands misaligned:\n\n  64 (NET_SKB_PAD) + 14 (ethernet) + 20 (IP) = 98\n\nSame for the XDP branch:\n\n  256 (XDP_PACKET_HEADROOM) + 14 (ethernet) + 20 (IP) = 290\n\nOn ARM32 this is fatal, because ldm and ldrd trap on unaligned addresses\neven when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is set.\n\nAny received echo request panics the machine, e.g:\n\n  Unhandled fault: alignment exception (0x001) at 0x81873062\n  Internal error: : 1 [#1] SMP ARM\n  Hardware name: Altera SOCFPGA Arria10\n  PC is at icmp_echo+0x38/0xa8\n  LR is at icmp_rcv+0x22c/0x370\n  Call trace:\n   icmp_echo from icmp_rcv+0x22c/0x370\n   icmp_rcv from ip_protocol_deliver_rcu+0x2c/0x224\n   ip_protocol_deliver_rcu from ip_local_deliver+0xc8/0x1a0\n   ip_local_deliver from ip_sublist_rcv_finish+0x3c/0x50\n   ip_sublist_rcv_finish from ip_list_rcv_finish+0x110/0x118\n   ip_list_rcv_finish from ip_list_rcv+0xc8/0xdc\n   ip_list_rcv from __netif_receive_skb_list_core+0x170/0x1c0\n   ...\n   napi_complete_done from stmmac_napi_poll_rx+0xcb0/0x1030\n  Code: e24dd068 e59020a0 e28dc010 e0822001 (e8920003)\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThe faulting instruction is the ldm of *icmp_hdr(skb) in icmp_echo().\n\nFix by adding NET_IP_ALIGN back to the RX offset, which restores the\nalignment the stack used to get.\n\nNote that commit a955318fe67e (\"stmmac: align RX buffers\") made a similar\nchange in 2021 and was reverted by commit 12d125b4574b (\"stmmac: Revert\n\"stmmac: align RX buffers\"\") because it caused packet corruption. That\npatch raised the offset from 0 without adjusting the buffer size\naccounting, so the DMA engine could arguably write past the end of the RX\nbuffers, though this was never root caused.\nCommit df542f669307 (\"net: stmmac: Switch to zero-copy in non-XDP RX\npath\") since derives the page pool allocation from stmmac_rx_offset(), so\nthe extra bytes are accounted for."
    }
  ],
  "lastModified": "2026-09-18T18:17:40.213",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}