{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/unix/garbage.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e3702470ced94fad74d71e2232f022d2eb752a6d",
              "status": "affected",
              "version": "4090fa373f0e763c43610853d2774b5979915959",
              "versionType": "git"
            },
            {
              "lessThan": "594d905195024b228c962627ae5ae7c17bd582a4",
              "status": "affected",
              "version": "4090fa373f0e763c43610853d2774b5979915959",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5dfd283f4651d04dbb70ceb9ae5c4a30eda3c52a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "de7921631ff323369aa63a4324695ab54ea4047e",
              "versionType": "git"
            },
            {
              "lessThan": "6.2",
              "status": "affected",
              "version": "6.1.141",
              "versionType": "semver"
            },
            {
              "lessThan": "6.7",
              "status": "affected",
              "version": "6.6.93",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/unix/garbage.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.10",
              "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": "7.1.10",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.1.141",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.6.93",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Unlink scc_entry in unix_del_edge().\n\nKyle Zeng reported that GC could free a dead SCC partially.\n\nThe scenario is as follows:\n\n   1) Create two SCCs:\n\n       X -.   A \u003c-\u003e B\n       ^--\u0027\n\n   2) Run the following concurrently:\n\n      2-1) send() sk-B to sk-B from sk-X\n      2-2) close() both A and B\n\nAt 2-1), there is a small window where unix_add_edges()\npublishes a new edge (B \u003c-\u003e B) to GC but its skb is not queued\nby skb_queue_tail().\n\nIf 2-2) completes before skb_queue_tail() and GC is triggered,\nit judges A \u003c-\u003e B as dead, but B is not freed because GC cannot\ncollect the not-yet-queued skb holding the B \u003c-\u003e B edge.\n\n       X -.   A \u003c-\u003e B -. This edge is visible\n       ^--\u0027         ^..\u0027  but skb is not\n\nThis itself is not a problem since the next GC run will judge\nB as dead as well and free it finally.\n\n       X -.   A \u003c.\u003e B -.\n       ^--\u0027         ^--\u0027\n\nHowever, X\u0027s SCC forces the next GC to call unix_walk_scc_fast(),\nand it iterates over A through B\u0027s scc_entry.\n\nLet\u0027s unlink scc_entry before freeing the vertex in unix_del_edge()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is only reachable through local AF_UNIX syscalls (socket/sendmsg with SCM_RIGHTS and close) that drive unix_add_edges(), unix_del_edge(), and unix_gc(); AF_UNIX is host-local IPC with no remote packet, Bluetooth, WiFi, or physical bus entry path.\nAC:L - Exploitation requires racing sendmsg() (scm_stat_add/unix_add_edges before skb_queue_tail) against concurrent close() that triggers GC; the attacker controls both threads, can pin CPUs, and can retry until the window is hit, so success does not depend on conditions outside attacker control.\nPR:L - An unprivileged local user can create AF_UNIX sockets, pass socket file descriptors via SCM_RIGHTS to form inflight reference cycles, and close sockets to schedule unix_gc(); no real-root capabilities, special namespaces, or non-default kernel configuration are required.\nUI:N - The attacker sets up the cyclic inflight graph, performs the concurrent self-send and close operations, and forces garbage collection from its own processes; no separate victim user action or cooperating peer is needed beyond the attacker\u0027s own sockets.\nS:U - The use-after-free corrupts kernel heap/list state during AF_UNIX garbage collection within the same kernel security authority; exploitation yields standard local privilege escalation rather than crossing a VM, IOMMU, or inter-tenant sandbox boundary.\nC:H - Freed struct unix_vertex objects remain linked through stale scc_entry; unix_walk_scc_fast(), unix_scc_dead(), and unix_collect_skb() dereference freed vertex-\u003eedges and predecessor socket receive queues, giving a slab UAF read primitive controllable through heap grooming.\nI:H - The same UAF enables reclaiming freed vertices and influencing GC list iteration and skb_queue_splice_init() during unix_collect_skb(), providing memory corruption primitives suitable for arbitrary kernel writes, control-flow hijack, and local privilege escalation.\nA:H - Iterating or collecting through a freed vertex reliably triggers kernel oops/panic (KASAN slab-use-after-free), and corrupt GC graph state can crash the host or deny service to local workloads even when full exploitation is not attempted."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:01:17.707Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e3702470ced94fad74d71e2232f022d2eb752a6d"
        },
        {
          "url": "https://git.kernel.org/stable/c/594d905195024b228c962627ae5ae7c17bd582a4"
        }
      ],
      "title": "af_unix: Unlink scc_entry in unix_del_edge().",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80521",
    "datePublished": "2026-08-26T14:37:02.589Z",
    "dateReserved": "2026-08-26T14:34:25.763Z",
    "dateUpdated": "2026-08-27T05:01:17.707Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}