CVE-2025-68262 (GCVE-0-2025-68262)

Vulnerability from cvelistv5 – Published: 2025-12-16 14:45 – Updated: 2026-05-11 21:49
VLAI
Title
crypto: zstd - fix double-free in per-CPU stream cleanup
Summary
In the Linux kernel, the following vulnerability has been resolved: crypto: zstd - fix double-free in per-CPU stream cleanup The crypto/zstd module has a double-free bug that occurs when multiple tfms are allocated and freed. The issue happens because zstd_streams (per-CPU contexts) are freed in zstd_exit() during every tfm destruction, rather than being managed at the module level. When multiple tfms exist, each tfm exit attempts to free the same shared per-CPU streams, resulting in a double-free. This leads to a stack trace similar to: BUG: Bad page state in process kworker/u16:1 pfn:106fd93 page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93 flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff) page_type: 0xffffffff() raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: nonzero entire_mapcount Modules linked in: ... CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G B Hardware name: ... Workqueue: btrfs-delalloc btrfs_work_helper Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 bad_page+0x71/0xd0 free_unref_page_prepare+0x24e/0x490 free_unref_page+0x60/0x170 crypto_acomp_free_streams+0x5d/0xc0 crypto_acomp_exit_tfm+0x23/0x50 crypto_destroy_tfm+0x60/0xc0 ... Change the lifecycle management of zstd_streams to free the streams only once during module cleanup.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7033 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f5ad93ffb54119a8dc5e18f070624d4ead586969 , < dc0f4509b0ed5d82bef78e058db0ac4df04d0695 (git)
Affected: f5ad93ffb54119a8dc5e18f070624d4ead586969 , < e983feaa79de1e46c9087fb9f02fedb0e5397ce6 (git)
Affected: f5ad93ffb54119a8dc5e18f070624d4ead586969 , < 48bc9da3c97c15f1ea24934bcb3b736acd30163d (git)
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Linux Linux Affected: 6.17
Unaffected: 0 , < 6.17 (semver)
Unaffected: 6.17.12 , ≤ 6.17.* (semver)
Unaffected: 6.18.1 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "crypto/zstd.c"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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          "versions": [
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              "version": "6.17"
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              "versionType": "semver"
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              "versionType": "semver"
            },
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              "versionType": "semver"
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                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: zstd - fix double-free in per-CPU stream cleanup\n\nThe crypto/zstd module has a double-free bug that occurs when multiple\ntfms are allocated and freed.\n\nThe issue happens because zstd_streams (per-CPU contexts) are freed in\nzstd_exit() during every tfm destruction, rather than being managed at\nthe module level.  When multiple tfms exist, each tfm exit attempts to\nfree the same shared per-CPU streams, resulting in a double-free.\n\nThis leads to a stack trace similar to:\n\n  BUG: Bad page state in process kworker/u16:1  pfn:106fd93\n  page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93\n  flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)\n  page_type: 0xffffffff()\n  raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000\n  raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000\n  page dumped because: nonzero entire_mapcount\n  Modules linked in: ...\n  CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G    B\n  Hardware name: ...\n  Workqueue: btrfs-delalloc btrfs_work_helper\n  Call Trace:\n   \u003cTASK\u003e\n   dump_stack_lvl+0x5d/0x80\n   bad_page+0x71/0xd0\n   free_unref_page_prepare+0x24e/0x490\n   free_unref_page+0x60/0x170\n   crypto_acomp_free_streams+0x5d/0xc0\n   crypto_acomp_exit_tfm+0x23/0x50\n   crypto_destroy_tfm+0x60/0xc0\n   ...\n\nChange the lifecycle management of zstd_streams to free the streams only\nonce during module cleanup."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T21:49:58.343Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/dc0f4509b0ed5d82bef78e058db0ac4df04d0695"
        },
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          "url": "https://git.kernel.org/stable/c/e983feaa79de1e46c9087fb9f02fedb0e5397ce6"
        },
        {
          "url": "https://git.kernel.org/stable/c/48bc9da3c97c15f1ea24934bcb3b736acd30163d"
        }
      ],
      "title": "crypto: zstd - fix double-free in per-CPU stream cleanup",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68262",
    "datePublished": "2025-12-16T14:45:04.198Z",
    "dateReserved": "2025-12-16T13:41:40.267Z",
    "dateUpdated": "2026-05-11T21:49:58.343Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-10-30",
      "epss": "0.00184",
      "percentile": "0.0798"
    },
    "nvd": {
      "cve": {
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: zstd - fix double-free in per-CPU stream cleanup\n\nThe crypto/zstd module has a double-free bug that occurs when multiple\ntfms are allocated and freed.\n\nThe issue happens because zstd_streams (per-CPU contexts) are freed in\nzstd_exit() during every tfm destruction, rather than being managed at\nthe module level.  When multiple tfms exist, each tfm exit attempts to\nfree the same shared per-CPU streams, resulting in a double-free.\n\nThis leads to a stack trace similar to:\n\n  BUG: Bad page state in process kworker/u16:1  pfn:106fd93\n  page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93\n  flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)\n  page_type: 0xffffffff()\n  raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000\n  raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000\n  page dumped because: nonzero entire_mapcount\n  Modules linked in: ...\n  CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G    B\n  Hardware name: ...\n  Workqueue: btrfs-delalloc btrfs_work_helper\n  Call Trace:\n   \u003cTASK\u003e\n   dump_stack_lvl+0x5d/0x80\n   bad_page+0x71/0xd0\n   free_unref_page_prepare+0x24e/0x490\n   free_unref_page+0x60/0x170\n   crypto_acomp_free_streams+0x5d/0xc0\n   crypto_acomp_exit_tfm+0x23/0x50\n   crypto_destroy_tfm+0x60/0xc0\n   ...\n\nChange the lifecycle management of zstd_streams to free the streams only\nonce during module cleanup."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ncrypto: zstd - correcci\u00f3n de doble liberaci\u00f3n en la limpieza de flujos por CPU\n\nEl m\u00f3dulo crypto/zstd tiene un error de doble liberaci\u00f3n que ocurre cuando se asignan y liberan m\u00faltiples tfms.\n\nEl problema ocurre porque los zstd_streams (contextos por CPU) se liberan en zstd_exit() durante cada destrucci\u00f3n de tfm, en lugar de ser gestionados a nivel de m\u00f3dulo. Cuando existen m\u00faltiples tfms, cada salida de tfm intenta liberar los mismos flujos compartidos por CPU, lo que resulta en una doble liberaci\u00f3n.\n\nEsto conduce a un seguimiento de pila similar a:\n\n  BUG: Estado de p\u00e1gina incorrecto en el proceso kworker/u16:1 pfn:106fd93\n  p\u00e1gina: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93\n  flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)\n  page_type: 0xffffffff()\n  raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000\n  raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000\n  p\u00e1gina volcada porque: entire_mapcount distinto de cero\n  M\u00f3dulos enlazados: ...\n  CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G    B\n  Nombre del hardware: ...\n  Cola de trabajo: btrfs-delalloc btrfs_work_helper\n  Traza de llamada:\n   \u003cTAREA\u003e\n   dump_stack_lvl+0x5d/0x80\n   bad_page+0x71/0xd0\n   free_unref_page_prepare+0x24e/0x490\n   free_unref_page+0x60/0x170\n   crypto_acomp_free_streams+0x5d/0xc0\n   crypto_acomp_exit_tfm+0x23/0x50\n   crypto_destroy_tfm+0x60/0xc0\n   ...\n\nCambiar la gesti\u00f3n del ciclo de vida de zstd_streams para liberar los flujos solo una vez durante la limpieza del m\u00f3dulo."
          }
        ],
        "id": "CVE-2025-68262",
        "lastModified": "2026-10-14T13:10:00.187",
        "metrics": {},
        "published": "2025-12-16T15:15:55.697",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/48bc9da3c97c15f1ea24934bcb3b736acd30163d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/e983feaa79de1e46c9087fb9f02fedb0e5397ce6"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-30T03:19:04+00:00",
      "cve": "CVE-2025-68262",
      "id": "CVE-2025-68262",
      "initial_release_date": "2025-12-16T14:45:04.198000+00:00",
      "product_status:known_affected": "280",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: crypto: zstd - fix double-free in per-CPU stream cleanup",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-68262.json",
      "version": "3"
    }
  }
}



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