CVE-2026-72431 (GCVE-0-2026-72431)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:14
VLAI
Title
alloc_tag: fix use-after-free in /proc/allocinfo after module unload
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 9f44df50fee4d2f6cb374177244ccfa9f0a5cc95 , < 37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f (git)
Affected: 9f44df50fee4d2f6cb374177244ccfa9f0a5cc95 , < 008ceffd44040f809aead6d7bef7cb1210c4149a (git)
Affected: 9f44df50fee4d2f6cb374177244ccfa9f0a5cc95 , < 2956268efc457cb05d29c1bf94de1e8e684d7bbc (git)
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Linux Linux Affected: 6.17
Unaffected: 0 , < 6.17 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
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          "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:14:31.058Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f"
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          "url": "https://git.kernel.org/stable/c/008ceffd44040f809aead6d7bef7cb1210c4149a"
        },
        {
          "url": "https://git.kernel.org/stable/c/2956268efc457cb05d29c1bf94de1e8e684d7bbc"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72431",
    "datePublished": "2026-08-15T05:56:46.821Z",
    "dateReserved": "2026-08-09T03:40:39.929Z",
    "dateUpdated": "2026-08-17T05:14:31.058Z",
    "state": "PUBLISHED"
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        "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",
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}



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