A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitive and complete system compromise. This flaw is only exploitable during the early boot phase, an attacker needs to perform a Man-in-the-Middle or compromise the boot server to be able to exploit this vulnerability successfully.
https://securityaffairs.com/158792/hacking/critical-shim-bug-linux.html?web_view=true
https://eclypsium.com/blog/the-real-shim-shady-how-cve-2023-40547-impacts-most-linux-systems/
https://lists.debian.org/debian-lts-announce/2024/05/msg00009.html
https://bugzilla.redhat.com/show_bug.cgi?id=2234589
https://access.redhat.com/security/cve/CVE-2023-40547
https://access.redhat.com/errata/RHSA-2024:2086
https://access.redhat.com/errata/RHSA-2024:1959
https://access.redhat.com/errata/RHSA-2024:1903
https://access.redhat.com/errata/RHSA-2024:1902
https://access.redhat.com/errata/RHSA-2024:1883
https://access.redhat.com/errata/RHSA-2024:1876
https://access.redhat.com/errata/RHSA-2024:1873
https://access.redhat.com/errata/RHSA-2024:1835