Vulnerability Details : 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 overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
Vulnerability category: Memory Corruption
Products affected by CVE-2021-3491
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:20.10:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:21.04:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-3491
0.01%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 1 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-3491
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
7.2
|
HIGH | AV:L/AC:L/Au:N/C:C/I:C/A:C |
3.9
|
10.0
|
NIST | |
|
8.8
|
HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
2.0
|
6.0
|
NIST | |
|
7.8
|
HIGH | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
1.1
|
6.0
|
Canonical Ltd. |
CWE ids for CVE-2021-3491
-
The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.Assigned by: security@ubuntu.com (Secondary)
-
The product writes data past the end, or before the beginning, of the intended buffer.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-3491
-
https://ubuntu.com/security/notices/USN-4949-1
USN-4949-1: Linux kernel vulnerabilities | Ubuntu security notices | UbuntuThird Party Advisory
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https://ubuntu.com/security/notices/USN-4950-1
USN-4950-1: Linux kernel vulnerabilities | Ubuntu security notices | UbuntuThird Party Advisory
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https://www.zerodayinitiative.com/advisories/ZDI-21-589/
ZDI-21-589 | Zero Day InitiativeThird Party Advisory;VDB Entry
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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d1f82808877bb10d3deee7cf3374a4eb3fb582db
kernel/git/torvalds/linux.git - Linux kernel source treePatch;Vendor Advisory
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https://security.netapp.com/advisory/ntap-20210716-0004/
June 2021 Linux Kernel 5.12.4 Vulnerabilities in NetApp Products | NetApp Product SecurityThird Party Advisory
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https://www.openwall.com/lists/oss-security/2021/05/11/13
oss-security - CVE-2021-3491 - Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypassMailing List;Patch;Third Party Advisory
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