Vulnerability CVE-2020-9391
Published: 2020-02-25

Description:
An issue was discovered in the Linux kernel 5.4 and 5.5 through 5.5.6 on the AArch64 architecture. It ignores the top byte in the address passed to the brk system call, potentially moving the memory break downwards when the application expects it to move upwards, aka CID-dcde237319e6. This has been observed to cause heap corruption with the GNU C Library malloc implementation.

Type:

CWE-119

 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

CVSS2 => (AV:L/AC:L/Au:N/C:N/I:N/A:P)

CVSS Base Score
Impact Subscore
Exploitability Subscore
2.1/10
2.9/10
3.9/10
Exploit range
Attack complexity
Authentication
Local
Low
No required
Confidentiality impact
Integrity impact
Availability impact
None
None
Partial
Affected software
Linux -> Linux kernel 
Fedoraproject -> Fedora 

 References:
http://www.openwall.com/lists/oss-security/2020/02/25/6
https://bugzilla.redhat.com/show_bug.cgi?id=1797052
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dcde237319e626d1ec3c9d8b7613032f0fd4663a
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/O4LH35HOPBJIKYHYFXMBBM75DN75PZHZ/
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