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GHSA-2H35-47M3-H9HP

Vulnerability from github – Published: 2026-09-03 15:32 – Updated: 2026-09-04 06:31

Details

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

ovpn: ensure socket is owned by ovpn before deref sk_user_data

Some subsystems, like BPF SOCKMAP, set sk_user_data without actually setting the encap_type.

For this reason, we must make sure that the type is the one ovpn expects before dereferencing sk_user_data.

Failing to do so may lead to out-of-bounds reads.

Severity

7.3 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80735"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-03T13:06:12Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: ensure socket is owned by ovpn before deref sk_user_data\n\nSome subsystems, like BPF SOCKMAP, set sk_user_data without\nactually setting the encap_type.\n\nFor this reason, we must make sure that the type is the\none ovpn expects before dereferencing sk_user_data.\n\nFailing to do so may lead to out-of-bounds reads.",
  "id": "GHSA-2h35-47m3-h9hp",
  "modified": "2026-09-04T06:31:20Z",
  "published": "2026-09-03T15:32:14Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80735"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/43a31142e1d22b3cf5490bd94a94db7196901734"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/59aed1eb60d70678a53acccb0cb337a26ce6680e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/61fb3cca40ff938671474f4a16adb908c19032d7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-80735 (GCVE-0-2026-80735)

Vulnerability from cvelistv5 – Published: 2026-09-03 08:21 – Updated: 2026-09-04 04:58

Title

ovpn: ensure socket is owned by ovpn before deref sk_user_data

Summary

In the Linux kernel, the following vulnerability has been resolved: ovpn: ensure socket is owned by ovpn before deref sk_user_data Some subsystems, like BPF SOCKMAP, set sk_user_data without actually setting the encap_type. For this reason, we must make sure that the type is the one ovpn expects before dereferencing sk_user_data. Failing to do so may lead to out-of-bounds reads.

Severity

7.3 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/61fb3cca40ff93867…
https://git.kernel.org/stable/c/43a31142e1d22b3cf…
https://git.kernel.org/stable/c/59aed1eb60d70678a…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f6226ae7a0cd47aaa9175aca6a1e19600f884cbf , < 61fb3cca40ff938671474f4a16adb908c19032d7 (git) Affected: f6226ae7a0cd47aaa9175aca6a1e19600f884cbf , < 43a31142e1d22b3cf5490bd94a94db7196901734 (git) Affected: f6226ae7a0cd47aaa9175aca6a1e19600f884cbf , < 59aed1eb60d70678a53acccb0cb337a26ce6680e (git)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/socket.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "61fb3cca40ff938671474f4a16adb908c19032d7",
              "status": "affected",
              "version": "f6226ae7a0cd47aaa9175aca6a1e19600f884cbf",
              "versionType": "git"
            },
            {
              "lessThan": "43a31142e1d22b3cf5490bd94a94db7196901734",
              "status": "affected",
              "version": "f6226ae7a0cd47aaa9175aca6a1e19600f884cbf",
              "versionType": "git"
            },
            {
              "lessThan": "59aed1eb60d70678a53acccb0cb337a26ce6680e",
              "status": "affected",
              "version": "f6226ae7a0cd47aaa9175aca6a1e19600f884cbf",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/socket.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.45",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: ensure socket is owned by ovpn before deref sk_user_data\n\nSome subsystems, like BPF SOCKMAP, set sk_user_data without\nactually setting the encap_type.\n\nFor this reason, we must make sure that the type is the\none ovpn expects before dereferencing sk_user_data.\n\nFailing to do so may lead to out-of-bounds reads."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The flaw is reached only via OVPN_CMD_PEER_NEW genetlink (local sendmsg/netlink syscall) that passes a UDP socket fd into ovpn_socket_new(); BPF SOCKMAP enrollment and ovpn setup are local kernel control paths, not remote packet handling.\nAC:L - An attacker who can use OVPN netlink and BPF SOCKMAP fully controls creating a UDP socket, enrolling it in sockmap (sk_user_data set, encap_type left zero), and issuing PEER_NEW, deterministically hitting the bad cast on each attempt.\nPR:L - All OVPN genetlink commands require GENL_ADMIN_PERM (CAP_NET_ADMIN), and BPF SOCKMAP enrollment needs bpf()/map privileges (CAP_BPF, often plus CAP_NET_ADMIN); both are obtainable by unprivileged users inside permitted user/network namespaces per CNA guidance.\nUI:N - No separate victim action is required; the same local actor creates the ovpn interface, enrolls their UDP socket in BPF SOCKMAP, and sends OVPN_CMD_PEER_NEW to trigger ovpn_socket_new() on that fd.\nS:U - Impact is confined to kernel memory misinterpretation within the host kernel security domain on VPN/offload nodes; it does not cross VM, container runtime, or IOMMU boundaries into another security authority.\nC:H - When sk_user_data points to a BPF sk_psock (or similar non-ovpn owner) but encap_type is zero, ovpn_socket_new() casts it to struct ovpn_socket and reads ovpn_sock-\u003eovpn, a type-confused out-of-bounds read of kernel memory per CNA OOB-read guidance.\nI:H - This is type confusion between foreign sk_user_data objects and struct ovpn_socket; CNA guidance rates type confusion High, and a mistaken ovpn_sock-\u003eovpn match could drive ovpn_socket_hold() against the wrong layout, corrupting refcount-adjacent kernel fields.\nA:L - The common path returns -EBUSY after the misread comparison, but the confused read and any mistaken hold can still provoke WARN/KASAN faults or refcount corruption on VPN gateways running ovpn offload with BPF sockmap, giving at least Low availability impact when uncertain."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-04T04:58:20.684Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/61fb3cca40ff938671474f4a16adb908c19032d7"
        },
        {
          "url": "https://git.kernel.org/stable/c/43a31142e1d22b3cf5490bd94a94db7196901734"
        },
        {
          "url": "https://git.kernel.org/stable/c/59aed1eb60d70678a53acccb0cb337a26ce6680e"
        }
      ],
      "title": "ovpn: ensure socket is owned by ovpn before deref sk_user_data",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80735",
    "datePublished": "2026-09-03T08:21:51.344Z",
    "dateReserved": "2026-08-26T14:34:25.789Z",
    "dateUpdated": "2026-09-04T04:58:20.684Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-2H35-47M3-H9HP

CVE-2026-80735 (GCVE-0-2026-80735)

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