DSA-4735-1 grub2 -- security update

Several vulnerabilities have been discovered in the GRUB2 bootloader. CVE-2020-10713 A flaw in the grub.cfg parsing code was found allowing to break UEFI Secure Boot and load arbitrary code. Details can be found at https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/ CVE-2020-14308 It was discovered that grub_malloc does not validate the allocation size allowing for arithmetic overflow and subsequently a heap-based buffer overflow. CVE-2020-14309 An integer overflow in grub_squash_read_symlink may lead to a heap based buffer overflow. CVE-2020-14310 An integer overflow in read_section_from_string may lead to a heap based buffer overflow. CVE-2020-14311 An integer overflow in grub_ext2_read_link may lead to a heap-based buffer overflow. CVE-2020-15706 script: Avoid a use-after-free when redefining a function during execution. CVE-2020-15707 An integer overflow flaw was found in the initrd size handling. Further detailed information can be found at https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot For the stable distribution (buster), these problems have been fixed in version 2.02+dfsg1-20+deb10u1. We recommend that you upgrade your grub2 packages. For the detailed security status of grub2 please refer to its security tracker page at: https://security-tracker.debian.org/tracker/grub2