FKIE_CVE-2026-46121

Vulnerability from fkie_nvd - Published: 2026-05-28 10:16 - Updated: 2026-05-28 13:44
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-schemes: protect memcg_path kfree() with damon_sysfs_lock Patch series "mm/damon/sysfs-schemes: fix use-after-free for [memcg_]path". Reads of 'memcg_path' and 'path' files in DAMON sysfs interface could race with their writes, results in use-after-free. Fix those. This patch (of 2): damon_sysfs_scheme_filter->mmecg_path can be read and written by users, via DAMON sysfs memcg_path file. It can also be indirectly read, for the parameters {on,off}line committing to DAMON. The reads for parameters committing are protected by damon_sysfs_lock to avoid the sysfs files being destroyed while any of the parameters are being read. But the user-driven direct reads and writes are not protected by any lock, while the write is deallocating the memcg_path-pointing buffer. As a result, the readers could read the already freed buffer (user-after-free). Note that the user-reads don't race when the same open file is used by the writer, due to kernfs's open file locking. Nonetheless, doing the reads and writes with separate open files would be common. Fix it by protecting both the user-direct reads and writes with damon_sysfs_lock.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1e68eb96e8beb1abefd12dd22c5637795d8a877e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b1e9f2d5870776347edef927f9bb3ea19b8e3abb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/baecc45ad60e621ef14d6c1e7f41ef36bbfdf910
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c88802d0e8edd14b6cd2daf3000f99adbc4c85c5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/eafd6f5372d29b0dd213799b92c2c9c7ad31d7da
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs-schemes: protect memcg_path kfree() with damon_sysfs_lock\n\nPatch series \"mm/damon/sysfs-schemes: fix use-after-free for [memcg_]path\".\n\nReads of \u0027memcg_path\u0027 and \u0027path\u0027 files in DAMON sysfs interface could race\nwith their writes, results in use-after-free.  Fix those.\n\n\nThis patch (of 2):\n\ndamon_sysfs_scheme_filter-\u003emmecg_path can be read and written by users,\nvia DAMON sysfs memcg_path file.  It can also be indirectly read, for the\nparameters {on,off}line committing to DAMON.  The reads for parameters\ncommitting are protected by damon_sysfs_lock to avoid the sysfs files\nbeing destroyed while any of the parameters are being read.  But the\nuser-driven direct reads and writes are not protected by any lock, while\nthe write is deallocating the memcg_path-pointing buffer.  As a result,\nthe readers could read the already freed buffer (user-after-free).  Note\nthat the user-reads don\u0027t race when the same open file is used by the\nwriter, due to kernfs\u0027s open file locking.  Nonetheless, doing the reads\nand writes with separate open files would be common.  Fix it by protecting\nboth the user-direct reads and writes with damon_sysfs_lock."
    }
  ],
  "id": "CVE-2026-46121",
  "lastModified": "2026-05-28T13:44:01.663",
  "metrics": {},
  "published": "2026-05-28T10:16:27.600",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1e68eb96e8beb1abefd12dd22c5637795d8a877e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b1e9f2d5870776347edef927f9bb3ea19b8e3abb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/baecc45ad60e621ef14d6c1e7f41ef36bbfdf910"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c88802d0e8edd14b6cd2daf3000f99adbc4c85c5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/eafd6f5372d29b0dd213799b92c2c9c7ad31d7da"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.