CVE-2021-47649 (GCVE-0-2021-47649)

Vulnerability from cvelistv5 – Published: 2025-02-26 01:54 – Updated: 2026-05-11 13:58
VLAI?
Title
udmabuf: validate ubuf->pagecount
Summary
In the Linux kernel, the following vulnerability has been resolved: udmabuf: validate ubuf->pagecount Syzbot has reported GPF in sg_alloc_append_table_from_pages(). The problem was in ubuf->pages == ZERO_PTR. ubuf->pagecount is calculated from arguments passed from user-space. If user creates udmabuf with list.size == 0 then ubuf->pagecount will be also equal to zero; it causes kmalloc_array() to return ZERO_PTR. Fix it by validating ubuf->pagecount before passing it to kmalloc_array().
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: fbb0de795078190a9834b3409e4b009cfb18a6d4 , < 5d50f851dd307c07ca5591297093f19967c834a9 (git)
Affected: fbb0de795078190a9834b3409e4b009cfb18a6d4 , < b267a8118c2b171bf7d67b90ed64154eeab9fae0 (git)
Affected: fbb0de795078190a9834b3409e4b009cfb18a6d4 , < 811b667cefbea9cb7511a874b169d6a92907137e (git)
Affected: fbb0de795078190a9834b3409e4b009cfb18a6d4 , < a3728d32fc61eb0fe283cb8ff60b2c8f751e2202 (git)
Affected: fbb0de795078190a9834b3409e4b009cfb18a6d4 , < 9e9b4a269f84d3230f2af84ff42322db676440d9 (git)
Affected: fbb0de795078190a9834b3409e4b009cfb18a6d4 , < 2b6dd600dd72573c23ea180b5b0b2f1813405882 (git)
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Linux Linux Affected: 4.20
Unaffected: 0 , < 4.20 (semver)
Unaffected: 5.4.189 , ≤ 5.4.* (semver)
Unaffected: 5.10.110 , ≤ 5.10.* (semver)
Unaffected: 5.15.33 , ≤ 5.15.* (semver)
Unaffected: 5.16.19 , ≤ 5.16.* (semver)
Unaffected: 5.17.2 , ≤ 5.17.* (semver)
Unaffected: 5.18 , ≤ * (original_commit_for_fix)
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  }
}


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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.

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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.



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