Vulnerability · Published Mar 3, 2021 · Assigned by redhat
CVE-2020-27749
Medium 6.7
In plain English
A medium-severity stack buffer overflow in grub2. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage, without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | shim-aa64 | 15.4-2.el8_1.alma | ALSA-2021:1734 |
| AlmaLinux:8 | shim-ia32 | 15.4-2.el8_1.alma | ALSA-2021:1734 |
| AlmaLinux:8 | shim-unsigned-aarch64 | 15-7.el8_1.alma | ALSA-2021:1734 |
| AlmaLinux:8 | shim-unsigned-x64 | 15.4-4.el8_1.alma | ALSA-2021:1734 |
| AlmaLinux:8 | shim-x64 | 15.4-2.el8_1.alma | ALSA-2021:1734 |
| Alpine:v3.20 | grub | 2.06-r0 | ALPINE-CVE-2020-27749 |
| Alpine:v3.21 | grub | 2.06-r0 | ALPINE-CVE-2020-27749 |
| Alpine:v3.22 | grub | 2.06-r0 | ALPINE-CVE-2020-27749 |
| Alpine:v3.23 | grub | 2.06-r0 | ALPINE-CVE-2020-27749 |
| Alpine:v3.24 | grub | 2.06-r0 | ALPINE-CVE-2020-27749 |
| Debian:12 | grub2 | 2.04-16 | DEBIAN-CVE-2020-27749 |
| Debian:13 | grub2 | 2.04-16 | DEBIAN-CVE-2020-27749 |
| Debian:14 | grub2 | 2.04-16 | DEBIAN-CVE-2020-27749 |
| Rocky Linux:8 | fwupd | 0:1.5.9-1.el8_4 | RLSA-2021:2566 |
| Rocky Linux:8 | shim-unsigned-aarch64 | 0:15-7.el8.1.1 | RLSA-2021:1734 |
Affected products (as reported)
Weakness: CWE-121
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1899966 x_refsource_MISC
- FEDORA-2021-cab258a413 vendor-advisory, x_refsource_FEDORA
- GLSA-202104-05 vendor-advisory, x_refsource_GENTOO
- https://security.netapp.com/advisory/ntap-20220325-0001/ x_refsource_CONFIRM