Vulnerability-Lookup

GHSA-PCF6-JJPM-2JRR

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32

Details

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72431"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:16Z",
    "severity": null
  },
  "details": "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": "GHSA-pcf6-jjpm-2jrr",
  "modified": "2026-08-15T06:32:24Z",
  "published": "2026-08-15T06:32:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72431"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/008ceffd44040f809aead6d7bef7cb1210c4149a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2956268efc457cb05d29c1bf94de1e8e684d7bbc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

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

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:14

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

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/37e3e8a2c3bfdd503…
https://git.kernel.org/stable/c/008ceffd44040f809…
https://git.kernel.org/stable/c/2956268efc457cb05…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9f44df50fee4d2f6cb374177244ccfa9f0a5cc95 , < 37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f (git) Affected: 9f44df50fee4d2f6cb374177244ccfa9f0a5cc95 , < 008ceffd44040f809aead6d7bef7cb1210c4149a (git) Affected: 9f44df50fee4d2f6cb374177244ccfa9f0a5cc95 , < 2956268efc457cb05d29c1bf94de1e8e684d7bbc (git)
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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:14:31.058Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f"
        },
        {
          "url": "https://git.kernel.org/stable/c/008ceffd44040f809aead6d7bef7cb1210c4149a"
        },
        {
          "url": "https://git.kernel.org/stable/c/2956268efc457cb05d29c1bf94de1e8e684d7bbc"
        }
      ],
      "title": "alloc_tag: fix use-after-free in /proc/allocinfo after module unload",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "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"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-PCF6-JJPM-2JRR

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

Tags

Sightings

Nomenclature