What is CVE-2021-3491?

CVE-2021-3491 is a high-severity vulnerability in Linux Kernel, classified under Incorrect Calculation of Buffer Size. CVSS score: 7.8/10. Published 2021-06-04.

How severe is CVE-2021-3491?

High severity. CVSS v3 base score is 7.8 out of 10.

Vulnerability in Linux Kernel

CVE-2021-3491

The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap o…

EPSS: 0.001 (18.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H.

Affected products

Linux Kernel — versions trunk, linux-5.12.y, linux-5.11.y

Weakness classification (CWE)

CWE-131 — Incorrect Calculation of Buffer Size

References

ubuntu.com/security/notices/USN-4950-1 (vendor-advisory, x_refsource_UBUNTU)
ubuntu.com/security/notices/USN-4949-1 (vendor-advisory, x_refsource_UBUNTU)
[oss-security] CVE-2021-3491 - Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass (mailing-list, x_refsource_MLIST)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ (x_refsource_MISC)
www.zerodayinitiative.com/advisories/ZDI-21-589/ (x_refsource_MISC)
security.netapp.com/advisory/ntap-20210716-0004/ (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2021-3491?: CVE-2021-3491 is a high-severity vulnerability in Linux Kernel, classified under Incorrect Calculation of Buffer Size. CVSS score: 7.8/10. Published 2021-06-04.
How severe is CVE-2021-3491?: High severity. CVSS v3 base score is 7.8 out of 10.