CVE-2026-31652 (GCVE-0-2026-31652)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:45 – Updated: 2026-04-24 14:45
VLAI?
Title
mm/damon/stat: deallocate damon_call() failure leaking damon_ctx
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/damon/stat: deallocate damon_call() failure leaking damon_ctx damon_stat_start() always allocates the module's damon_ctx object (damon_stat_context). Meanwhile, if damon_call() in the function fails, the damon_ctx object is not deallocated. Hence, if the damon_call() is failed, and the user writes Y to “enabled” again, the previously allocated damon_ctx object is leaked. This cannot simply be fixed by deallocating the damon_ctx object when damon_call() fails. That's because damon_call() failure doesn't guarantee the kdamond main function, which accesses the damon_ctx object, is completely finished. In other words, if damon_stat_start() deallocates the damon_ctx object after damon_call() failure, the not-yet-terminated kdamond could access the freed memory (use-after-free). Fix the leak while avoiding the use-after-free by keeping returning damon_stat_start() without deallocating the damon_ctx object after damon_call() failure, but deallocating it when the function is invoked again and the kdamond is completely terminated. If the kdamond is not yet terminated, simply return -EAGAIN, as the kdamond will soon be terminated. The issue was discovered [1] by sashiko.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 405f61996d9d2e9d497cd9f6b66f41dc28d3d1d8 , < 447f8870b484f6596d7a7130e72bd0a3f1e037bb (git)
Affected: 405f61996d9d2e9d497cd9f6b66f41dc28d3d1d8 , < 16c92e9bf55fa049ddb5e894dc0623dacd46a620 (git)
Affected: 405f61996d9d2e9d497cd9f6b66f41dc28d3d1d8 , < 4c04c6b47c361612b1d70cec8f7a60b1482d1400 (git)
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    Linux Linux Affected: 6.17
Unaffected: 0 , < 6.17 (semver)
Unaffected: 6.18.23 , ≤ 6.18.* (semver)
Unaffected: 6.19.13 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "mm/damon/stat.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/stat: deallocate damon_call() failure leaking damon_ctx\n\ndamon_stat_start() always allocates the module\u0027s damon_ctx object\n(damon_stat_context).  Meanwhile, if damon_call() in the function fails,\nthe damon_ctx object is not deallocated.  Hence, if the damon_call() is\nfailed, and the user writes Y to \u201cenabled\u201d again, the previously\nallocated damon_ctx object is leaked.\n\nThis cannot simply be fixed by deallocating the damon_ctx object when\ndamon_call() fails.  That\u0027s because damon_call() failure doesn\u0027t guarantee\nthe kdamond main function, which accesses the damon_ctx object, is\ncompletely finished.  In other words, if damon_stat_start() deallocates\nthe damon_ctx object after damon_call() failure, the not-yet-terminated\nkdamond could access the freed memory (use-after-free).\n\nFix the leak while avoiding the use-after-free by keeping returning\ndamon_stat_start() without deallocating the damon_ctx object after\ndamon_call() failure, but deallocating it when the function is invoked\nagain and the kdamond is completely terminated.  If the kdamond is not yet\nterminated, simply return -EAGAIN, as the kdamond will soon be terminated.\n\nThe issue was discovered [1] by sashiko."
        }
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        "dateUpdated": "2026-04-24T14:45:04.930Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/4c04c6b47c361612b1d70cec8f7a60b1482d1400"
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      "title": "mm/damon/stat: deallocate damon_call() failure leaking damon_ctx",
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    "cveId": "CVE-2026-31652",
    "datePublished": "2026-04-24T14:45:04.930Z",
    "dateReserved": "2026-03-09T15:48:24.128Z",
    "dateUpdated": "2026-04-24T14:45:04.930Z",
    "state": "PUBLISHED"
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      "date": "2026-04-25",
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  }
}


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  • 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.



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