CVE-2026-31635

Estado: ModificadaAlta (7.5)—

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

rxrpc: fix oversized RESPONSE authenticator length check

rxgk_verify_response() decodes auth_len from the packet and is supposed to verify that it fits in the remaining bytes. The existing check is inverted, so oversized RESPONSE authenticators are accepted and passed to rxgk_decrypt_skb(), which can later reach skb_to_sgvec() with an impossible length and hit BUG_ON(len).

Decoded from the original latest-net reproduction logs with scripts/decode_stacktrace.sh:

RIP: __skb_to_sgvec() [net/core/skbuff.c:5285 (discriminator 1)] Call Trace: skb_to_sgvec() [net/core/skbuff.c:5305] rxgk_decrypt_skb() [net/rxrpc/rxgk_common.h:81] rxgk_verify_response() [net/rxrpc/rxgk.c:1268] rxrpc_process_connection() [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364 net/rxrpc/conn_event.c:386] process_one_work() [kernel/workqueue.c:3281] worker_thread() [kernel/workqueue.c:3353 kernel/workqueue.c:3440] kthread() [kernel/kthread.c:436] ret_from_fork() [arch/x86/kernel/process.c:164]

Leer descripción completaMostrar menos

Reject authenticator lengths that exceed the remaining packet payload.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.63%
Percentil entre todas las CVEs puntuadas: 48
Fecha de la puntuación: 5/10/2026

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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access85 %
Impacto principalT1499.004 Application or System Exploitationimpact90 %

Vulnerabilidad de red sin autenticación (AV:N/PR:N/UI:N) en kernel Linux rxrpc. Atacante remoto envía paquete RESPONSE con authenticator oversized que causa BUG_ON en skb_to_sgvec(), generando Denial of Service por crash del kernel.

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

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

NVD-CWE-noinfo
CWE-130

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-31635",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-31635",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-18T00:00:00+00:00"
        }
      }
    ],
    "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": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "lessThan": "beee051f259acd286fed64c32c2b31e6f5097eb5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "lessThan": "e2f1a80d8b1ed6a5ae585a399c2b46500bdcc305",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a",
              "lessThan": "a2567217ade970ecc458144b6be469bc015b23e5",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/rxrpc/rxgk.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.23",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19.13",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/rxrpc/rxgk.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-04-24T15:16:42.820",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/a2567217ade970ecc458144b6be469bc015b23e5",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/beee051f259acd286fed64c32c2b31e6f5097eb5",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e2f1a80d8b1ed6a5ae585a399c2b46500bdcc305",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://github.com/v12-security/pocs/tree/main/dirtydecrypt",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    },
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-130"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: fix oversized RESPONSE authenticator length check\n\nrxgk_verify_response() decodes auth_len from the packet and is supposed\nto verify that it fits in the remaining bytes. The existing check is\ninverted, so oversized RESPONSE authenticators are accepted and passed\nto rxgk_decrypt_skb(), which can later reach skb_to_sgvec() with an\nimpossible length and hit BUG_ON(len).\n\nDecoded from the original latest-net reproduction logs with\nscripts/decode_stacktrace.sh:\n\nRIP: __skb_to_sgvec()\n  [net/core/skbuff.c:5285 (discriminator 1)]\nCall Trace:\n skb_to_sgvec() [net/core/skbuff.c:5305]\n rxgk_decrypt_skb() [net/rxrpc/rxgk_common.h:81]\n rxgk_verify_response() [net/rxrpc/rxgk.c:1268]\n rxrpc_process_connection()\n   [net/rxrpc/conn_event.c:266 net/rxrpc/conn_event.c:364\n    net/rxrpc/conn_event.c:386]\n process_one_work() [kernel/workqueue.c:3281]\n worker_thread()\n   [kernel/workqueue.c:3353 kernel/workqueue.c:3440]\n kthread() [kernel/kthread.c:436]\n ret_from_fork() [arch/x86/kernel/process.c:164]\n\nReject authenticator lengths that exceed the remaining packet payload."
    }
  ],
  "lastModified": "2026-06-17T10:34:08.150",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "EAE31F43-AAC5-4801-B2B2-119D62A532A2",
              "versionEndExcluding": "6.18.23",
              "versionStartIncluding": "6.16.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "1490EF9B-9080-481C-8D22-1306AAE664E4",
              "versionEndExcluding": "6.19.13",
              "versionStartIncluding": "6.19"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.16:-:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6238B17D-C12B-458F-A138-97039BFC4595"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}