# CVE-2023-4194: Kernel: tap: tap_open(): correctly initialize socket uid next fix of i_uid to current_fsuid

Status: published. Published: 2023-08-07. Updated: 2026-11-02.

A flaw was found in the Linux kernel's TUN/TAP functionality. This issue could allow a local user to bypass network filters and gain unauthorized access to some resources. The original patches fixing CVE-2023-1076 are incorrect or incomplete. The problem is that the following upstream commits - a096ccca6e50 ("tun: tun_chr_open(): correctly initialize socket uid"), - 66b2c338adce ("tap: tap_open(): correctly initialize socket uid"), pass "inode->i_uid" to sock_init_data_uid() as the last parameter and that turns out to not be accurate.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: secalert@redhat.com) — https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: secalert@redhat.com) — https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: secalert@redhat.com) — https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: af854a3a-2127-422b-91ae-364da2661108) — https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: af854a3a-2127-422b-91ae-364da2661108) — https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: af854a3a-2127-422b-91ae-364da2661108) — https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 9 (kernel): ≥ 0:5.14.0-362.8.1.el9_3; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (kernel-rt): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (kernel-rt): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (kernel-rt): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Virtualization 4 (redhat-virtualization-host): Version range not reported. Source: CNA: redhat

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndIncluding": "6.4",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:6.5:rc1:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:6.5:rc2:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:6.5:rc3:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:6.5:rc4:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  },
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  },
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  },
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N; source: CNA: redhat

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N; source: NVD: nvd@nist.gov

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.27% as of 2026-11-02; percentile 18.89%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-843

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2023:6583 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2023-4194 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2229498 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/ (CNA: redhat)

- https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/ (CNA: redhat)

- https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/ (CNA: redhat)

- https://access.redhat.com/errata/RHSA-2023:6583 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/security/cve/CVE-2023-4194 (ADP: CVE; vdb-entry, x_refsource_REDHAT, x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=2229498 (ADP: CVE; issue-tracking, x_refsource_REDHAT, x_transferred)

- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html (ADP: CVE; x_transferred)

- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/344H6HO6SSC4KT7PDFXSDIXKMKHISSGF/ (ADP: CVE; x_transferred)

- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3TYLSJ2SAI7RF56ZLQ5CQWCJLVJSD73Q/ (ADP: CVE; x_transferred)

- https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/ (ADP: CVE; x_transferred)

- https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/ (ADP: CVE; x_transferred)

- https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/ (ADP: CVE; x_transferred)

- https://security.netapp.com/advisory/ntap-20231027-0002/ (ADP: CVE; x_transferred)

- https://www.debian.org/security/2023/dsa-5480 (ADP: CVE; x_transferred)

- https://www.debian.org/security/2023/dsa-5492 (ADP: CVE; x_transferred)

- https://access.redhat.com/errata/RHSA-2023:6583 (secalert@redhat.com; Third Party Advisory)

- https://access.redhat.com/security/cve/CVE-2023-4194 (secalert@redhat.com; Third Party Advisory)

- https://bugzilla.redhat.com/show_bug.cgi?id=2229498 (secalert@redhat.com; Issue Tracking, Third Party Advisory)

- https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/ (secalert@redhat.com; Mailing List, Patch, Vendor Advisory)

- https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/ (secalert@redhat.com; Mailing List, Patch, Vendor Advisory)

- https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/ (secalert@redhat.com; Mailing List, Patch, Vendor Advisory)

- https://access.redhat.com/errata/RHSA-2023:6583 (af854a3a-2127-422b-91ae-364da2661108; Third Party Advisory)

- https://access.redhat.com/security/cve/CVE-2023-4194 (af854a3a-2127-422b-91ae-364da2661108; Third Party Advisory)

- https://bugzilla.redhat.com/show_bug.cgi?id=2229498 (af854a3a-2127-422b-91ae-364da2661108; Issue Tracking, Third Party Advisory)

- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html (af854a3a-2127-422b-91ae-364da2661108)

- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/344H6HO6SSC4KT7PDFXSDIXKMKHISSGF/ (af854a3a-2127-422b-91ae-364da2661108)

- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3TYLSJ2SAI7RF56ZLQ5CQWCJLVJSD73Q/ (af854a3a-2127-422b-91ae-364da2661108)

- https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/ (af854a3a-2127-422b-91ae-364da2661108; Mailing List, Patch, Vendor Advisory)

- https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/ (af854a3a-2127-422b-91ae-364da2661108; Mailing List, Patch, Vendor Advisory)

- https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/ (af854a3a-2127-422b-91ae-364da2661108; Mailing List, Patch, Vendor Advisory)

- https://security.netapp.com/advisory/ntap-20231027-0002/ (af854a3a-2127-422b-91ae-364da2661108)

- https://www.debian.org/security/2023/dsa-5480 (af854a3a-2127-422b-91ae-364da2661108)

- https://www.debian.org/security/2023/dsa-5492 (af854a3a-2127-422b-91ae-364da2661108)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2023-4194; retrieved 2026-11-02; source updated 2026-11-02

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4194; retrieved 2026-11-03; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2023-4194; retrieved 2026-11-02; source updated Not reported

Revision: c6f464b344799338ad8d7f1c80a76192316bcbe79a7cc2fae0f6f7f7de7a8977

Canonical: https://y2.dev/cve/CVE-2023-4194

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