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FKIE_CVE-2026-72431

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: alloc_tag: fix use-after-free in /proc/allocinfo after module unload allocinfo_start() only reinitializes the codetag iterator at position 0. For subsequent reads (position > 0), it reuses cached iterator state from the previous batch. allocinfo_stop() drops mod_lock between read batches, which allows module unload to complete and free the module memory that the cached iterator still references: CPU0 (read) CPU1 (rmmod) ---- ---- allocinfo_start(pos=0) down_read(mod_lock) allocinfo_show() ... allocinfo_stop() up_read(mod_lock) codetag_unload_module() kfree(cmod) release_module_tags() ... free_mod_mem() allocinfo_start(pos=N) down_read(mod_lock) // reuses cached iter, skips re-init allocinfo_show() ct->filename <-- UAF After free_mod_mem() frees the module's .rodata, allocinfo_show() dereferences ct->filename, ct->function which point there. Save the iterator state in allocinfo_next() and resume from it in allocinfo_start() with codetag_next_ct(), which detects module removal via idr_find() returning NULL and skips to the next module.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/008ceffd44040f809aead6d7bef7cb1210c4149a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2956268efc457cb05d29c1bf94de1e8e684d7bbc
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "lib/alloc_tag.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f",
              "status": "affected",
              "version": "9f44df50fee4d2f6cb374177244ccfa9f0a5cc95",
              "versionType": "git"
            },
            {
              "lessThan": "008ceffd44040f809aead6d7bef7cb1210c4149a",
              "status": "affected",
              "version": "9f44df50fee4d2f6cb374177244ccfa9f0a5cc95",
              "versionType": "git"
            },
            {
              "lessThan": "2956268efc457cb05d29c1bf94de1e8e684d7bbc",
              "status": "affected",
              "version": "9f44df50fee4d2f6cb374177244ccfa9f0a5cc95",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "lib/alloc_tag.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "lessThan": "6.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nalloc_tag: fix use-after-free in /proc/allocinfo after module unload\n\nallocinfo_start() only reinitializes the codetag iterator at position 0. \nFor subsequent reads (position \u003e 0), it reuses cached iterator state from\nthe previous batch.  allocinfo_stop() drops mod_lock between read batches,\nwhich allows module unload to complete and free the module memory that the\ncached iterator still references:\n\n  CPU0 (read)                        CPU1 (rmmod)\n  ----                               ----\n  allocinfo_start(pos=0)\n    down_read(mod_lock)\n    allocinfo_show()\n    ...\n  allocinfo_stop()\n    up_read(mod_lock)\n                                     codetag_unload_module()\n                                       kfree(cmod)\n                                       release_module_tags()\n                                     ...\n                                     free_mod_mem()\n  allocinfo_start(pos=N)\n    down_read(mod_lock)\n    // reuses cached iter, skips re-init\n  allocinfo_show()\n    ct-\u003efilename   \u003c-- UAF\n\nAfter free_mod_mem() frees the module\u0027s .rodata, allocinfo_show()\ndereferences ct-\u003efilename, ct-\u003efunction which point there.\n\nSave the iterator state in allocinfo_next() and resume from it in\nallocinfo_start() with codetag_next_ct(), which detects module removal via\nidr_find() returning NULL and skips to the next module."
    }
  ],
  "id": "CVE-2026-72431",
  "lastModified": "2026-08-17T06:19:10.443",
  "metrics": {},
  "published": "2026-08-15T06:22:16.960",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/008ceffd44040f809aead6d7bef7cb1210c4149a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2956268efc457cb05d29c1bf94de1e8e684d7bbc"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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