CVE-2021-47040: linux kernel Buffer Overflow — Fix

Description

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.

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CVSS v3.1 Score

7.8

HIGH

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

Weakness Type (CWE)

CWE-120 CWE-120

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.8 — 5.10.37
linux	linux_kernel	5.11 — 5.11.21
linux	linux_kernel	5.12 — 5.12.4

References

Advisories & Patches

https://git.kernel.org/stable/c/38134ada0ceea3e848fe993263c0ff6207fd46e7 https://git.kernel.org/stable/c/51bf90901952aaac564bbdb36b2b503050c53dd9 https://git.kernel.org/stable/c/84b8c266c4bfe9ed5128e13253c388deb74b1b03 https://git.kernel.org/stable/c/cbbc13b115b8f18e0a714d89f87fbdc499acfe2d https://git.kernel.org/stable/c/38134ada0ceea3e848fe993263c0ff6207fd46e7 https://git.kernel.org/stable/c/51bf90901952aaac564bbdb36b2b503050c53dd9 https://git.kernel.org/stable/c/84b8c266c4bfe9ed5128e13253c388deb74b1b03 https://git.kernel.org/stable/c/cbbc13b115b8f18e0a714d89f87fbdc499acfe2d

Frequently Asked Questions

What is CVE-2021-47040? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47040? +

CVE-2021-47040 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2021-47040? +

CVE-2021-47040 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47040? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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