The spectre_v2_select_mitigation function in arch/x86/kernel/cpu/bugs.c in the Linux kernel before 4.18.1 does not always fill RSB upon a context switch, which makes it easier for attackers to conduct userspace-userspace spectreRSB attacks.
| Software | From | Fixed in |
|---|---|---|
| debian / debian_linux | 8.0 | 8.0.x |
| debian / debian_linux | 9.0 | 9.0.x |
| canonical / ubuntu_linux | 16.04 | 16.04.x |
| canonical / ubuntu_linux | 14.04 | 14.04.x |
| canonical / ubuntu_linux | 12.04 | 12.04.x |
| canonical / ubuntu_linux | 18.04 | 18.04.x |
| linux / linux_kernel | - | 4.18.1 |