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Review reviewHigh

CVE-2021-47040

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix overflows checks in provide buffers Colin reported before possible overflow and sign extension problems in io_provide_buffers_prep(). As Linus pointed out previous attempt did nothing useful, see d81269fecb8ce ("io_uring: fix provide_buffers sign extension"). Do that with help of check_<op>_overflow helpers. And fix struct io_provide_buf::len type, as it doesn't make much sense to keep it signed.

CVSS
7.8
EPSS
0.26%
17.5% percentile
CISA KEV
Not listed
Published
2024.02.28
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.26%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix overflows checks in provide buffers Colin reported before possible overflow and sign extension problems in io_provide_buffers_prep(). As Linus pointed out previous attempt did nothing useful, see d81269fecb8ce ("io_uring: fix provide_buffers sign extension"). Do that with help of check_<op>_overflow helpers. And fix struct io_provide_buf::len type, as it doesn't make much sense to keep it signed.

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff < cbbc13b115b8f18e0a714d89f87fbdc499acfe2d, >= efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff < 51bf90901952aaac564bbdb36b2b503050c53dd9, >= efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff < 84b8c266c4bfe9ed5128e13253c388deb74b1b03, >= efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff < 38134ada0ceea3e848fe993263c0ff6207fd46e7, >= 5.8, >= 5.8 < 5.10.37, >= 5.11 < 5.11.21, >= 5.12 < 5.12.4
Fixed versions
5.10.37, 5.11.21, 5.12.4

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-120