CVE-2026-53075 (GCVE-0-2026-53075)
Vulnerability from cvelistv5
Published
2026-06-24 16:30
Modified
2026-08-05 12:33
Severity ?
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ppp: require CAP_NET_ADMIN in target netns for unattached ioctls /dev/ppp open is currently authorized against file->f_cred->user_ns, while unattached administrative ioctls operate on current->nsproxy->net_ns. As a result, a local unprivileged user can create a new user namespace with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace, and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against an inherited network namespace. Require CAP_NET_ADMIN in the user namespace that owns the target network namespace before handling unattached PPP administrative ioctls. This preserves normal pppd operation in the network namespace it is actually privileged in, while rejecting the userns-only inherited-netns case.
References
Impacted products
Vendor Product Version
Linux Linux Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
Version: 273ec51dd7ceaa76e038875d85061ec856d8905e
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ppp/ppp_generic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "273ec51dd7ceaa76e038875d85061ec856d8905e",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "273ec51dd7ceaa76e038875d85061ec856d8905e",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "273ec51dd7ceaa76e038875d85061ec856d8905e",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "273ec51dd7ceaa76e038875d85061ec856d8905e",
              "versionType": "git"
            },
            {
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            {
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ppp/ppp_generic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.30"
            },
            {
              "lessThan": "2.6.30",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.258",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.141",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.91",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.258",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.209",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.141",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.91",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.33",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.10",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "2.6.30",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nppp: require CAP_NET_ADMIN in target netns for unattached ioctls\n\n/dev/ppp open is currently authorized against file-\u003ef_cred-\u003euser_ns,\nwhile unattached administrative ioctls operate on current-\u003ensproxy-\u003enet_ns.\n\nAs a result, a local unprivileged user can create a new user namespace\nwith CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace,\nand still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against\nan inherited network namespace.\n\nRequire CAP_NET_ADMIN in the user namespace that owns the target network\nnamespace before handling unattached PPP administrative ioctls.\n\nThis preserves normal pppd operation in the network namespace it is\nactually privileged in, while rejecting the userns-only inherited-netns\ncase."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable PPP administrative ioctls are reached locally through `/dev/ppp` and the `ioctl` syscall, not by remote packets.\nAC:L - An attacker can deterministically create a user namespace, open `/dev/ppp`, and issue the unattached ioctls against the inherited target network namespace; no race or external condition is required.\nPR:L - A basic unprivileged local user can gain `CAP_NET_ADMIN` only inside a new user namespace and abuse the pre-fix check, so this does not require real root or host `CAP_NET_ADMIN`.\nUI:N - No victim action is required after the attacker has local code execution; the attacker directly invokes the namespace and ioctl operations.\nS:C - The bug crosses the user-namespace capability boundary by allowing capabilities in one user namespace to administer PPP resources in a network namespace owned by another user namespace.\nC:H - By attaching to existing PPP units or channels, an attacker can read PPP control/authentication traffic and can plausibly expose sensitive PPP-session data in affected deployments.\nI:H - The attacker can create PPP interfaces, attach to units/channels, alter PPP parameters, and inject or redirect PPP frames in a network namespace they should not administer.\nA:H - The attacker can disrupt PPP connectivity by changing interface/channel state, disconnecting or bridging channels, or exhausting PPP resources, causing loss of network availability in PPP-dependent systems."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:33:07.985Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c9edd90c57ae23692fff6b049fdfa4572a9fd532"
        },
        {
          "url": "https://git.kernel.org/stable/c/5080e188c914110034bbc569d5cfa2f06204681d"
        },
        {
          "url": "https://git.kernel.org/stable/c/67e901e28d177ac9a9bed76d69ce3471e704a89e"
        },
        {
          "url": "https://git.kernel.org/stable/c/954745d0223e7caec917c0b2d1a889ff56fa6e54"
        },
        {
          "url": "https://git.kernel.org/stable/c/3b2c2157dc2afc5c17cd7238afefca92f1ef330e"
        },
        {
          "url": "https://git.kernel.org/stable/c/5013be175c7ffd8b39efbc3c9c4db5b10b85fea8"
        },
        {
          "url": "https://git.kernel.org/stable/c/1a8a51ce85075a56a743b6f142606dd2696a391c"
        },
        {
          "url": "https://git.kernel.org/stable/c/2bb6379416fd19f44c3423a00bfd8626259f6067"
        }
      ],
      "title": "ppp: require CAP_NET_ADMIN in target netns for unattached ioctls",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53075",
    "datePublished": "2026-06-24T16:30:16.214Z",
    "dateReserved": "2026-06-09T07:44:35.383Z",
    "dateUpdated": "2026-08-05T12:33:07.985Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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