bpf, arm64: Fix fp initialization for exception boundary

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Fix fp initialization for exception boundary In the ARM64 BPF JIT when prog->aux->exception_boundary is set for a BPF program, find_used_callee_regs() is not called because for a program acting as exception boundary, all callee saved registers are saved. find_used_callee_regs() sets `ctx->fp_used = true;` when it sees FP being used in any of the instructions. For programs acting as exception boundary, ctx->fp_used remains false even if frame pointer is used by the program and therefore, FP is not set-up for such programs in the prologue. This can cause the kernel to crash due to a pagefault. Fix it by setting ctx->fp_used = true for exception boundary programs as fp is always saved in such programs.

Timeline

1. Aug 19, 2025, 5:03 PM UTCCVE published
2. Oct 15, 2026, 9:52 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 15, 2026, 10:02 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 5d4fa9ec5643a5c75d3c1e6abf50fb9284caf1ff · fixed in 0dbef493cae7d451f740558665893c000adb2321; From 5d4fa9ec5643a5c75d3c1e6abf50fb9284caf1ff · fixed in e23184725dbb72d5d02940222eee36dbba2aa422; From 5d4fa9ec5643a5c75d3c1e6abf50fb9284caf1ff · fixed in 1ce30231e0a2c8c361ee5f8f7f265fc17130adce; From 5d4fa9ec5643a5c75d3c1e6abf50fb9284caf1ff · fixed in b114fcee766d5101eada1aca7bb5fd0a86c89b35

• Linux Linux

  6.12

• KernelLinux

  From 6.12.0 · fixed in 6.12.42; From 6.13.0 · fixed in 6.15.10; From 6.16.0 · fixed in 6.16.1

References 4