CVE-2021-47281 (GCVE-0-2021-47281)

Vulnerability from cvelistv5 – Published: 2024-05-21 14:20 – Updated: 2025-05-04 07:07
VLAI?
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently. For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < bd7d88b0874f82f7b29d1a53e574cedaf23166ba (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 536a7646c00a0f14fee49e5e313109e5da2f6031 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 83e197a8414c0ba545e7e3916ce05f836f349273 (git)
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    Linux Linux Unaffected: 5.10.44 , ≤ 5.10.* (semver)
Unaffected: 5.12.11 , ≤ 5.12.* (semver)
Unaffected: 5.13 , ≤ * (original_commit_for_fix)
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      "cveMetadata": "{\"cveId\": \"CVE-2021-47281\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2024-08-04T05:32:08.027Z\", \"dateReserved\": \"2024-05-21T13:27:52.128Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-05-21T14:20:07.499Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


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Sightings

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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.