Medium [CVE-2020-10781] flaw was found in the Linux Kernel before 5.8-rc6 in the ZRAM kernel module, where a user with a local account and the ability to read the /sys/class/zram-control/hot_add file can create ZRAM device nodes in the /dev/ directory
This medium-severity Red Hat Linux advisory covers CVE-2020-10781 affecting Red Hat Enterprise Linux 5, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
A flaw was found in the Linux Kernel before 5.8-rc6 in the ZRAM kernel module, where a user with a local account and the ability to read the /sys/class/zram-control/hot_add file can create ZRAM device nodes in the /dev/ directory. This read allocates kernel memory and is not accounted for a user that triggers the creation of that ZRAM device.
With this vulnerability, continually reading the device may consume a large amount of system memory and cause the Out-of-Memory (OOM) killer to activate and terminate random userspace processes, possibly making the system inoperable.
This flaw is rated as having Low impact, because it is a denial of service only and requires the ZRAM kernel module to be loaded, which it is not the default, and oading kernel modules is a privileged operation. Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-732. Affected Red Hat products: Red Hat Enterprise Linux 5; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise MRG 2.
Will not fix / out of support: Red Hat Enterprise Linux 5; Red Hat Enterprise Linux 6; Red Hat Enterprise MRG 2. Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: kernel-alt; Red Hat package: kernel-rt.
- < 5.8-rc6
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
Mitigation checklist
- Changing permissions on the files within /sys will prevent regular users from being able to trigger this issue, however permissions changed within /sys do not persist between reboots and will need to be reapplied after each boot.
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
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