CVE-2026-53389 (GCVE-0-2026-53389)
Vulnerability from cvelistv5
Published
2026-07-19 12:01
Modified
2026-08-17 04:50
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net/tcp-ao: fix use-after-free of key in del_async path In tcp_ao_delete_key(), the del_async path skips the current_key and rnext_key validity checks present in the synchronous path, assuming these pointers are always NULL on LISTEN sockets. However, if a key was added with set_current=1/set_rnext=1 while the socket was in CLOSE state, current_key and rnext_key will be non-NULL after listen() transitions the socket to LISTEN. When such a key is deleted with del_async=1, hlist_del_rcu() and call_rcu() free the key without clearing the dangling pointers. After the RCU grace period, getsockopt(TCP_AO_INFO) dereferences current_key->sndid and rnext_key->rcvid from freed slab memory. Clear current_key and rnext_key in the del_async path when they reference the key being deleted.
References
Impacted products
Vendor Product Version
Linux Linux Version: d6732b95b6fbbc6d5bb9d2f809e275763640c4a2
Version: d6732b95b6fbbc6d5bb9d2f809e275763640c4a2
Version: d6732b95b6fbbc6d5bb9d2f809e275763640c4a2
Version: d6732b95b6fbbc6d5bb9d2f809e275763640c4a2
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp_ao.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp_ao.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "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": "6.12.95",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.38",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.3",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp-ao: fix use-after-free of key in del_async path\n\nIn tcp_ao_delete_key(), the del_async path skips the current_key\nand rnext_key validity checks present in the synchronous path,\nassuming these pointers are always NULL on LISTEN sockets.  However,\nif a key was added with set_current=1/set_rnext=1 while the socket\nwas in CLOSE state, current_key and rnext_key will be non-NULL\nafter listen() transitions the socket to LISTEN.\n\nWhen such a key is deleted with del_async=1, hlist_del_rcu() and\ncall_rcu() free the key without clearing the dangling pointers.\nAfter the RCU grace period, getsockopt(TCP_AO_INFO) dereferences\ncurrent_key-\u003esndid and rnext_key-\u003ercvid from freed slab memory.\n\nClear current_key and rnext_key in the del_async path when they\nreference the key being deleted."
        }
      ],
      "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 - Exploitation requires local `setsockopt`/`getsockopt` syscalls on a TCP socket owned by the attacker; the UAF is triggered in socket-option management, not by remote TCP-AO packet processing on the listen path.\nAC:L - An attacker who controls the socket can deterministically perform add-with-set_current/set_rnext on CLOSE, listen(), del_async delete, wait for RCU, then getsockopt(TCP_AO_INFO) without depending on conditions outside their control.\nPR:L - No capability checks protect TCP-AO socket options beyond socket ownership; an unprivileged local user (including in a user namespace) can create a listening TCP socket, configure TCP-AO keys, and trigger the bug on their own socket.\nUI:N - No victim interaction is required; the attacker drives the full exploit sequence through their own socket file descriptor.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same security domain; this is not a cross-VM, cross-container, or IOMMU boundary escape.\nC:H - The bug is a use-after-free where `getsockopt(TCP_AO_INFO)` reads `sndid`/`rcvid` from freed `tcp_ao_key` slab memory, enabling information disclosure from attacker-influenced freed heap contents.\nI:H - Use-after-free of a heap-allocated `tcp_ao_key` structure can be leveraged with heap grooming for arbitrary memory corruption and potential kernel code execution, not merely a bounded write.\nA:H - Dereferencing freed kernel memory via `getsockopt(TCP_AO_INFO)` can cause kernel oops/panic and denial of service even when full exploitation is not attempted."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:50:40.399Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6ce7ef41743740ce15c2061561b784148b565b3f"
        },
        {
          "url": "https://git.kernel.org/stable/c/e77fbefd1269b5c123e7c651a1ebdce1b87d19a0"
        },
        {
          "url": "https://git.kernel.org/stable/c/7ddc29a094d96e9b3aa280433c6dc443df9eabf2"
        },
        {
          "url": "https://git.kernel.org/stable/c/5ba9950bc9078e19b69cca1e56d1553b125c6857"
        }
      ],
      "title": "net/tcp-ao: fix use-after-free of key in del_async path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53389",
    "datePublished": "2026-07-19T12:01:54.386Z",
    "dateReserved": "2026-06-09T07:44:35.402Z",
    "dateUpdated": "2026-08-17T04:50:40.399Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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