CVE-2026-68341 (GCVE-0-2026-68341)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:03 – Updated: 2026-08-17 05:03
VLAI
Title
ovpn: fix use after free in unlock_ovpn()
Summary
In the Linux kernel, the following vulnerability has been resolved: ovpn: fix use after free in unlock_ovpn() unlock_ovpn() iterates over the release_list using llist_for_each_entry() and drops the peer reference inside the loop body via ovpn_peer_put(). If this drops the last reference, the peer is eventually freed. However, llist_for_each_entry() reads peer->release_entry.next in the loop advance expression, which runs after the body. By that time the peer may have already been freed, resulting in a use after free when advancing to the next list entry. Fix this by using llist_for_each_entry_safe(), which caches the next pointer before executing the loop body.
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 80747caef33d77f5c1b3d24644e6d7dae69066b5 , < 5b96227c0e8b212b74838424c929fc889aedb555 (git)
Affected: 80747caef33d77f5c1b3d24644e6d7dae69066b5 , < 4cdb209f12a89c5faf9be0c45edb90ccdf65db0c (git)
Affected: 80747caef33d77f5c1b3d24644e6d7dae69066b5 , < e1ad6fe5db719874efa45b2caf9934552e09fc43 (git)
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Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 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/peer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5b96227c0e8b212b74838424c929fc889aedb555",
              "status": "affected",
              "version": "80747caef33d77f5c1b3d24644e6d7dae69066b5",
              "versionType": "git"
            },
            {
              "lessThan": "4cdb209f12a89c5faf9be0c45edb90ccdf65db0c",
              "status": "affected",
              "version": "80747caef33d77f5c1b3d24644e6d7dae69066b5",
              "versionType": "git"
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              "status": "affected",
              "version": "80747caef33d77f5c1b3d24644e6d7dae69066b5",
              "versionType": "git"
            }
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
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            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "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: fix use after free in unlock_ovpn()\n\nunlock_ovpn() iterates over the release_list using llist_for_each_entry()\nand drops the peer reference inside the loop body via ovpn_peer_put().\n\nIf this drops the last reference, the peer is eventually freed. However,\nllist_for_each_entry() reads peer-\u003erelease_entry.next in the loop advance\nexpression, which runs after the body. By that time the peer may have\nalready been freed, resulting in a use after free when advancing to the\nnext list entry.\n\nFix this by using llist_for_each_entry_safe(), which caches the next\npointer before executing the loop body."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - unlock_ovpn() is reached directly from remote-peer activity: a malformed/aborted OpenVPN TCP stream schedules ovpn_tcp_peer_del_work() -\u003e ovpn_peer_del() (tcp.c:154/287/506), peer disconnect hits ovpn_tcp_close(), and remote peers falling silent make ovpn_peer_keepalive_work() queue peers onto release_list. No local action is needed to enter the vulnerable loop.\nAC:L - The attacker controls both the trigger and its repetition rate: a remote peer can force transport errors, reconnects and keepalive expiries arbitrarily often, and in MP mode can control how many peers land on release_list at once, plus generate traffic-driven allocation pressure to influence slab reuse of the freed ovpn_peer.\nPR:L - The vulnerable loop only runs for peers already installed in the kernel, which the openvpn userspace daemon does for a connected client, so the attacker acts as an established (low-privileged) VPN peer rather than an unauthenticated stranger; no administrative rights on the target are needed.\nUI:N - Peer removal and the subsequent list walk happen automatically inside the kernel\u0027s TCP error/close handling and keepalive worker; no administrator or user action on the victim host is required.\nS:U - The use-after-free corrupts kernel heap state within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed ovpn_peer is re-read to obtain the next list pointer, so a reclaimed and re-populated slab object lets the attacker steer the walk onto arbitrary memory that is then dereferenced (peer-\u003esock, peer-\u003erefcount), yielding a kernel-memory read primitive and disclosure of sensitive kernel data.\nI:H - Continuing the walk onto a stale/attacker-groomed object causes rcu_replace_pointer() writes, lock_sock() and kref_put() (a controlled decrement plus invocation of a release callback) on a bogus struct ovpn_peer, giving heap-spray-based write and control-flow-hijack potential typical of exploitable UAFs.\nA:H - Dereferencing freed or recycled memory as an ovpn_peer reliably produces oops/panic or slab corruption, taking down the VPN gateway kernel; the path is remotely repeatable, so it is a dependable denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:03:41.213Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5b96227c0e8b212b74838424c929fc889aedb555"
        },
        {
          "url": "https://git.kernel.org/stable/c/4cdb209f12a89c5faf9be0c45edb90ccdf65db0c"
        },
        {
          "url": "https://git.kernel.org/stable/c/e1ad6fe5db719874efa45b2caf9934552e09fc43"
        }
      ],
      "title": "ovpn: fix use after free in unlock_ovpn()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68341",
    "datePublished": "2026-08-10T12:03:17.821Z",
    "dateReserved": "2026-07-30T09:28:09.384Z",
    "dateUpdated": "2026-08-17T05:03:41.213Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-22",
      "epss": "0.00566",
      "percentile": "0.45729"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/net/ovpn/peer.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "versionType": "git"
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              },
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                "product": "Linux",
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                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "version": "7.1.6",
                    "versionType": "semver"
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                    "version": "7.2",
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                  }
                ]
              }
            ],
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          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: fix use after free in unlock_ovpn()\n\nunlock_ovpn() iterates over the release_list using llist_for_each_entry()\nand drops the peer reference inside the loop body via ovpn_peer_put().\n\nIf this drops the last reference, the peer is eventually freed. However,\nllist_for_each_entry() reads peer-\u003erelease_entry.next in the loop advance\nexpression, which runs after the body. By that time the peer may have\nalready been freed, resulting in a use after free when advancing to the\nnext list entry.\n\nFix this by using llist_for_each_entry_safe(), which caches the next\npointer before executing the loop body."
          }
        ],
        "id": "CVE-2026-68341",
        "lastModified": "2026-08-17T06:17:42.307",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-08-10T13:20:24.613",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/4cdb209f12a89c5faf9be0c45edb90ccdf65db0c"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5b96227c0e8b212b74838424c929fc889aedb555"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-31T11:22:40+00:00",
      "cve": "CVE-2026-68341",
      "id": "CVE-2026-68341",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_not_affected": "277",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ovpn: fix use after free in unlock_ovpn()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68341.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-11T23:47:12Z",
      "cve": "CVE-2026-68341",
      "id": "CVE-2026-68341",
      "initial_release_date": "2026-08-11T23:47:12Z",
      "product_status:known_not_affected": "296",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68341",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68341.json",
      "version": "2"
    }
  }
}



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