Executive brief
A vulnerability in the Linux kernel's networking component for IBM Z systems (IUCV) could allow a local user to cause a system crash or potentially access sensitive information. The issue stems from how the system manages processor information in memory, which can lead to a stack overflow under specific configurations. This could impact the stability and availability of servers running affected Linux distributions.
Technical details
A vulnerability exists in the net/iucv component of the Linux kernel where cpumask variables are explicitly allocated on the stack. In kernel configurations where CONFIG_CPUMASK_OFFSTACK=y, these structures can be large enough to trigger a stack overflow. An attacker with local access could exploit this behavior to cause a denial of service (system crash) or potentially achieve out-of-bounds memory access. The fix replaces explicit stack allocation with the *cpumask_var API family, which ensures memory is allocated safely according to the kernel configuration. Patches have been released across multiple stable kernel branches.
Affected products
- Linux Linux Kernel up to 4.19.317, 4.20 to 5.4.279, 5.5 to 5.10.221, 5.11 to 5.15.162, 5.16 to 6.1.97, 6.2 to 6.6.37, 6.7 to 6.9.8
Timeline
- 2024-03-31: other: Initial patch submitted by developer
- 2024-07-05: patched: Patches committed to stable kernel trees
- 2024-07-29: disclosed: CVE published
References
- https://git.kernel.org/stable/c/0af718a690acc089aa1bbb95a93df833d864ef53
- https://git.kernel.org/stable/c/2b085521be5292016097b5e7ca81b26be3f7098d
- https://git.kernel.org/stable/c/2d090c7f7be3b26fcb80ac04d08a4a8062b1d959
- https://git.kernel.org/stable/c/724e7965af054079242b8d6f7e50ee226730a756
- https://git.kernel.org/stable/c/842afb47d84536fc976fece8fb6c54bea711ad1a
- https://git.kernel.org/stable/c/9dadab0db7d904413ea1cdaa13f127da05c31e71
- https://git.kernel.org/stable/c/be4e1304419c99a164b4c0e101c7c2a756b635b9