CVE-2022-28736 There's a use-after-free vulnerability in grub_cmd_chainloader() function
An attacker with local access can trigger a use-after-free in GRUB2's chainloader command to achieve arbitrary code execution or expose sensitive data.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-28736?
CVE-2022-28736 is a medium-severity use after free vulnerability in GNU GRUB, published on 20 Jul 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
There's a use-after-free vulnerability in grub_cmd_chainloader() function; The chainloader command is used to boot up operating systems that doesn't support multiboot and do not have direct support from GRUB2. When executing chainloader more than once a use-after-free vulnerability is triggered. If an attacker can control the GRUB2's memory allocation pattern sensitive data may be exposed and arbitrary code execution can be achieved.
Weakness: CWE-416
Which versions are affected by CVE-2022-28736?
It affects 1 product.
Products include Gnu Grub2.
How do I fix CVE-2022-28736?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2022-28736 being exploited?
There is no known exploitation of CVE-2022-28736 in the wild and no public exploit code.
Other vulnerabilities in GNU GRUB
- CVE-2024-56737 Memory corruption in GRUB2
- CVE-2022-28733 Integer underflow in grub_net_recv_ip4_packets
- CVE-2022-28734 Out-of-bounds write when handling split HTTP headers
- CVE-2025-61662 Grub2: missing unregister call for gettext command may lead to use-after-free
- CVE-2024-45782 Grub2: fs/hfs: strcpy() using the volume name (fs/hfs.c:382)
Sources
Also known as AZL-27554, AZL-34791, DEBIAN-CVE-2022-28736, GHSA-ff72-fwj3-6gh6, UBUNTU-CVE-2022-28736.