{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/trace/trace_events_synth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9fe183f659a2704255e5d84f6ae308c234a113ec",
              "status": "affected",
              "version": "27c888da9867725784bad3d6455d6e53b425fa2b",
              "versionType": "git"
            },
            {
              "lessThan": "8826d9e7bd51e7656f78baa4472e8e2f5e7069f0",
              "status": "affected",
              "version": "27c888da9867725784bad3d6455d6e53b425fa2b",
              "versionType": "git"
            },
            {
              "lessThan": "4ccf11c4e8a8e051499d53a12f502196c97a758e",
              "status": "affected",
              "version": "27c888da9867725784bad3d6455d6e53b425fa2b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/trace/trace_events_synth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.24",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.2.*",
              "status": "unaffected",
              "version": "6.2.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.24",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.2.11",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.3",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/synthetic: Fix races on freeing last_cmd\n\nCurrently, the \"last_cmd\" variable can be accessed by multiple processes\nasynchronously when multiple users manipulate synthetic_events node\nat the same time, it could lead to use-after-free or double-free.\n\nThis patch add \"lastcmd_mutex\" to prevent \"last_cmd\" from being accessed\nasynchronously.\n\n================================================================\n\nIt\u0027s easy to reproduce in the KASAN environment by running the two\nscripts below in different shells.\n\nscript 1:\n        while :\n        do\n                echo -n -e \u0027\\x88\u0027 \u003e /sys/kernel/tracing/synthetic_events\n        done\n\nscript 2:\n        while :\n        do\n                echo -n -e \u0027\\xb0\u0027 \u003e /sys/kernel/tracing/synthetic_events\n        done\n\n================================================================\ndouble-free scenario:\n\n    process A                       process B\n-------------------               ---------------\n1.kstrdup last_cmd\n                                  2.free last_cmd\n3.free last_cmd(double-free)\n\n================================================================\nuse-after-free scenario:\n\n    process A                       process B\n-------------------               ---------------\n1.kstrdup last_cmd\n                                  2.free last_cmd\n3.tracing_log_err(use-after-free)\n\n================================================================\n\nAppendix 1. KASAN report double-free:\n\nBUG: KASAN: double-free in kfree+0xdc/0x1d4\nFree of addr ***** by task sh/4879\nCall trace:\n        ...\n        kfree+0xdc/0x1d4\n        create_or_delete_synth_event+0x60/0x1e8\n        trace_parse_run_command+0x2bc/0x4b8\n        synth_events_write+0x20/0x30\n        vfs_write+0x200/0x830\n        ...\n\nAllocated by task 4879:\n        ...\n        kstrdup+0x5c/0x98\n        create_or_delete_synth_event+0x6c/0x1e8\n        trace_parse_run_command+0x2bc/0x4b8\n        synth_events_write+0x20/0x30\n        vfs_write+0x200/0x830\n        ...\n\nFreed by task 5464:\n        ...\n        kfree+0xdc/0x1d4\n        create_or_delete_synth_event+0x60/0x1e8\n        trace_parse_run_command+0x2bc/0x4b8\n        synth_events_write+0x20/0x30\n        vfs_write+0x200/0x830\n        ...\n\n================================================================\nAppendix 2. KASAN report use-after-free:\n\nBUG: KASAN: use-after-free in strlen+0x5c/0x7c\nRead of size 1 at addr ***** by task sh/5483\nsh: CPU: 7 PID: 5483 Comm: sh\n        ...\n        __asan_report_load1_noabort+0x34/0x44\n        strlen+0x5c/0x7c\n        tracing_log_err+0x60/0x444\n        create_or_delete_synth_event+0xc4/0x204\n        trace_parse_run_command+0x2bc/0x4b8\n        synth_events_write+0x20/0x30\n        vfs_write+0x200/0x830\n        ...\n\nAllocated by task 5483:\n        ...\n        kstrdup+0x5c/0x98\n        create_or_delete_synth_event+0x80/0x204\n        trace_parse_run_command+0x2bc/0x4b8\n        synth_events_write+0x20/0x30\n        vfs_write+0x200/0x830\n        ...\n\nFreed by task 5480:\n        ...\n        kfree+0xdc/0x1d4\n        create_or_delete_synth_event+0x74/0x204\n        trace_parse_run_command+0x2bc/0x4b8\n        synth_events_write+0x20/0x30\n        vfs_write+0x200/0x830\n        ..."
        }
      ],
      "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 triggered only by write() to the tracefs node /sys/kernel/tracing/synthetic_events (or dynamic_events), which requires local access to the machine\u0027s filesystem. There is no network-facing consumer of this code path.\nAC:L - Although it is a race, the attacker owns both sides \u2014 simply running two concurrent writers of malformed commands, exactly as the reporter\u0027s two-shell reproducer does, and the commit states it reproduces easily. Object size and contents of the raced allocation are fully attacker-chosen, so no condition lies outside the attacker\u0027s control.\nPR:L - No capability check exists in the path; access is gated only by DAC on the tracefs file, and tracefs\u0027s gid= mount option is explicitly provided so a non-root tracing group (Android/ChromeOS/developer-group deployments) can write these nodes. An unprivileged member of that group can trigger the race with plain writes.\nUI:N - The attacker performs the entire attack with its own write() calls; no victim action, mount, or file-open by another user is needed.\nS:U - The corruption occurs in kernel slab memory and its impact stays within the same kernel security authority, with no crossing of a hypervisor, IOMMU, or sandbox boundary.\nC:H - The use-after-free reads freed heap memory via strlen()/snprintf() in tracing_log_err() and copies it into err-\u003ecmd, which userspace can then read back from tracing/error_log \u2014 a direct kernel heap infoleak. Combined with the double-free\u0027s ability to overlap allocations, arbitrary kernel memory disclosure is achievable.\nI:H - The double-free frees an attacker-sized, attacker-filled kmalloc object twice, corrupting the SLUB freelist and letting two live allocations alias the same memory \u2014 a well-known route to arbitrary kernel write and control-flow hijack.\nA:H - The double-free and use-after-free readily produce slab corruption, KASAN BUG reports, and kernel panics, and the race can be re-triggered in a tight loop to reliably crash the system."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T09:14:16.799Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9fe183f659a2704255e5d84f6ae308c234a113ec"
        },
        {
          "url": "https://git.kernel.org/stable/c/8826d9e7bd51e7656f78baa4472e8e2f5e7069f0"
        },
        {
          "url": "https://git.kernel.org/stable/c/4ccf11c4e8a8e051499d53a12f502196c97a758e"
        }
      ],
      "title": "tracing/synthetic: Fix races on freeing last_cmd",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53478",
    "datePublished": "2025-10-01T11:42:47.185Z",
    "dateReserved": "2025-10-01T11:39:39.401Z",
    "dateUpdated": "2026-08-05T09:14:16.799Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}