There is an issue on grub2 before version 2.06 at function read_section_as_string(). It expects a font name to be at max UINT32_MAX - 1 length in bytes but it doesn't verify it before proceed with buffer allocation to read the value from the font value. An attacker may leverage that by crafting a malicious font file which has a name with UINT32_MAX, leading to read_section_as_string() to an arithmetic overflow, zero-sized allocation and further heap-based buffer overflow.
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
| Link | Tags |
|---|---|
| https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-14310 | vendor advisory issue tracking |
| https://usn.ubuntu.com/4432-1/ | third party advisory vendor advisory |
| http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00017.html | vendor advisory mailing list third party advisory |
| http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00016.html | vendor advisory mailing list third party advisory |
| https://security.gentoo.org/glsa/202104-05 | third party advisory vendor advisory |