CVE-2026-72431
alloc_tag: fix use-after-free in /proc/allocinfo after module unload
Description
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.
INFO
Published Date :
Aug. 15, 2026, 6:22 a.m.
Last Modified :
Aug. 17, 2026, 6:19 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Save iterator state in allocinfo_next().
- Resume iterator state in allocinfo_start().
- Detect module removal using idr_find().
- Skip to next module upon detection.
References to Advisories, Solutions, and Tools
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CVE-2026-72431.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-72431 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-72431
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-72431 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-72431 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f', 'versionType': 'git'}, {'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '008ceffd44040f809aead6d7bef7cb1210c4149a', 'versionType': 'git'}, {'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '2956268efc457cb05d29c1bf94de1e8e684d7bbc', 'versionType': 'git'}], 'programFiles': ['lib/alloc_tag.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.17'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.17', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['lib/alloc_tag.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f', 'versionType': 'git'}, {'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '008ceffd44040f809aead6d7bef7cb1210c4149a', 'versionType': 'git'}, {'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '2956268efc457cb05d29c1bf94de1e8e684d7bbc', 'versionType': 'git'}], 'programFiles': ['lib/alloc_tag.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.17'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.17', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['lib/alloc_tag.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 15, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f', 'versionType': 'git'}, {'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '008ceffd44040f809aead6d7bef7cb1210c4149a', 'versionType': 'git'}, {'status': 'affected', 'version': '9f44df50fee4d2f6cb374177244ccfa9f0a5cc95', 'lessThan': '2956268efc457cb05d29c1bf94de1e8e684d7bbc', 'versionType': 'git'}], 'programFiles': ['lib/alloc_tag.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.17'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.17', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['lib/alloc_tag.c'], 'defaultStatus': 'affected'}] Added Description 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. Added Reference https://git.kernel.org/stable/c/008ceffd44040f809aead6d7bef7cb1210c4149a Added Reference https://git.kernel.org/stable/c/2956268efc457cb05d29c1bf94de1e8e684d7bbc Added Reference https://git.kernel.org/stable/c/37e3e8a2c3bfdd503209f043f8bbfbdcf5a1d92f