Executive brief
A vulnerability in the Linux kernel's kexec component could allow a local user to trigger a system warning or kernel instability. kexec is a mechanism used to boot into a new kernel from a currently running one. This issue occurs when the system incorrectly handles specific memory sections during the boot preparation process, potentially leading to operational disruptions.
Technical details
A vulnerability in kexec_load_purgatory() in the Linux kernel arises when deriving image->start by locating e_entry within an SHF_EXECINSTR section. If a purgatory object contains multiple executable sections with overlapping sh_addr, the entrypoint check can match multiple times, triggering a WARN_ON. The fix modifies the logic to derive the entry section from the 'purgatory_start' symbol when present, ensuring a unique and correct entry point calculation. This is a local vulnerability requiring the ability to initiate a kexec file load. Patches have been released across multiple stable kernel branches.
Affected products
- Linux Linux Kernel Fixed in various stable branches including 6.x and 5.x
Timeline
- 2026-01-20: disclosed: Initial patch submission by Li Chen
- 2026-03-04: patched: Commits merged into stable branches by Sasha Levin
- 2026-05-08: advisory: CVE-2026-43289 published
References
- https://git.kernel.org/stable/c/027797595a108726f4a0a45d225f603b0ffbd22b
- https://git.kernel.org/stable/c/1737d37ae1d2814e6cf0a1af87af3d41f0812b95
- https://git.kernel.org/stable/c/36eb314184a0ae74dd42914b47d2b9fc43be8034
- https://git.kernel.org/stable/c/480e1d5c64bb14441f79f2eb9421d5e26f91ea3d
- https://git.kernel.org/stable/c/5226570bd252cea2e805a161cb0f75c204c3108a
- https://git.kernel.org/stable/c/875355152b33436907c2a6d2ffad1431fa86c62b
- https://git.kernel.org/stable/c/cfccd3b8c51bc57a8a6fcb2fd30453afae5bc0d2