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CVE-2021-47604 (GCVE-0-2021-47604)

Vulnerability from cvelistv5 – Published: 2024-06-19 14:54 – Updated: 2026-08-05 08:48
VLAI
Title
vduse: check that offset is within bounds in get_config()
Summary
In the Linux kernel, the following vulnerability has been resolved: vduse: check that offset is within bounds in get_config() This condition checks "len" but it does not check "offset" and that could result in an out of bounds read if "offset > dev->config_size". The problem is that since both variables are unsigned the "dev->config_size - offset" subtraction would result in a very high unsigned value. I think these checks might not be necessary because "len" and "offset" are supposed to already have been validated using the vhost_vdpa_config_validate() function. But I do not know the code perfectly, and I like to be safe.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-09-10 17:12 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c8a6153b6c59d95c0e091f053f6f180952ade91e , < ebbbc5fea3f648175df1aa3f127c78eb0252cc2a (git)
Affected: c8a6153b6c59d95c0e091f053f6f180952ade91e , < dc1db0060c02d119fd4196924eff2d1129e9a442 (git)
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Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 5.15.11 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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no race or other condition beyond attacker control is required.\\nPR:L - Exploitation requires access to vhost-vdpa/VDUSE device nodes that are commonly granted to non-root virtualization users (e.g., qemu/kvm group), not capabilities that are only available to real root in the init user namespace.\\nUI:N - No victim interaction is needed; the attacker triggers the OOB read directly via ioctl or by attaching/probing the malicious VDUSE device.\\nS:U - Impact is confined to the host kernel and the calling process (kernel memory disclosure or oops); this does not cross a VM/IOMMU/sandbox security authority boundary by itself.\\nC:H - The underflow allows an unbounded out-of-bounds read from kernel memory past the config buffer, and on the vhost-vdpa path that data is copied to userspace via copy_to_user, enabling arbitrary kernel memory disclosure.\\nI:N - The bug is a pure out-of-bounds read (memcpy from config+offset into a destination buffer) with no write primitive or integrity modification of kernel state.\\nA:H - A sufficiently large or far OOB read can access unmapped memory and cause a kernel oops/panic, resulting in a full denial of service.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"c8a6153b6c59d95c0e091f053f6f180952ade91e\", \"lessThan\": \"ebbbc5fea3f648175df1aa3f127c78eb0252cc2a\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"c8a6153b6c59d95c0e091f053f6f180952ade91e\", \"lessThan\": \"dc1db0060c02d119fd4196924eff2d1129e9a442\", \"versionType\": \"git\"}], \"programFiles\": [\"drivers/vdpa/vdpa_user/vduse_dev.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.15\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.15\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.15.11\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"5.16\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"drivers/vdpa/vdpa_user/vduse_dev.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/ebbbc5fea3f648175df1aa3f127c78eb0252cc2a\"}, {\"url\": \"https://git.kernel.org/stable/c/dc1db0060c02d119fd4196924eff2d1129e9a442\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nvduse: check that offset is within bounds in get_config()\\n\\nThis condition checks \\\"len\\\" but it does not check \\\"offset\\\" and that\\ncould result in an out of bounds read if \\\"offset \u003e dev-\u003econfig_size\\\".\\nThe problem is that since both variables are unsigned the\\n\\\"dev-\u003econfig_size - offset\\\" subtraction would result in a very high\\nunsigned value.\\n\\nI think these checks might not be necessary because \\\"len\\\" and \\\"offset\\\"\\nare supposed to already have been validated using the\\nvhost_vdpa_config_validate() function.  But I do not know the code\\nperfectly, and I like to be safe.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.11\", \"versionStartIncluding\": \"5.15\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.16\", \"versionStartIncluding\": \"5.15\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T08:48:33.959Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-47604\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T08:48:33.959Z\", \"dateReserved\": \"2024-05-24T15:11:00.736Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-06-19T14:54:03.664Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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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.