mm/slub: reset KASAN tag in defer_free() before accessing freed memory

{
  "id": "94a43f8cce9374d1a682812fba395b5dc88b909ac9978aec78676284fec212de",
  "url": "https://osv.dev/vulnerability/CVE-2025-71110",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mm/slub: reset KASAN tag in defer_free() before accessing freed memory",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mm/slub: reset KASAN tag in defer_free() before accessing freed memory When CONFIG_SLUB_TINY is enabled, kfree_nolock() calls kasan_slab_free() before defer_free(). On ARM64 with MTE (Memory Tagging Extension), kasan_slab_free() poisons the memory and changes the tag from the original (e.g., 0xf3) to a poison tag (0xfe). When defer_free() then tries to write to the freed object to build the deferred free list via llist_add(), the pointer still has the old tag, causing a tag mismatch and triggering a KASAN use-after-free report: BUG: KASAN: slab-use-after-free in defer_free+0x3c/0xbc mm/slub.c:6537 Write at addr f3f000000854f020 by task kworker/u8:6/983 Pointer tag: [f3], memory tag: [fe] Fix this by calling kasan_reset_tag() before accessing the freed memory. This is safe because defer_free() is part of the allocator itself and is expected to manipulate freed memory for bookkeeping purposes.",
    "evidence": "osv:CVE-2025-71110",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-71110",
      "aliases": [
        "CVE-2025-71110"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "af92793e52c3a99b828ed4bdd277fd3e11c18d08"
                },
                {
                  "fixed": "65d4e5af2a2e82f4fc50d8259aee208fbc6b2c1d"
                },
                {
                  "fixed": "53ca00a19d345197a37a1bf552e8d1e7b091666c"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-71110.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.18.0"
                },
                {
                  "fixed": "6.18.3"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-71110.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:46.198732178Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/53ca00a19d345197a37a1bf552e8d1e7b091666c",
        "https://git.kernel.org/stable/c/65d4e5af2a2e82f4fc50d8259aee208fbc6b2c1d",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71110.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-71110",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71110.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-71110",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 513984,
  "published_at": "2026-01-14T15:05:57.952+00:00"
}