Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: csky: Fix a4/a5 restoration in syscall trace path The syscall trace path reloads syscall arguments from pt_regs before calling the syscall handler. On C-SKY ABIv2, the 5th and 6th syscall arguments are prepared as stack arguments before invoking syscallid. The current code adjusts sp before loading LSAVE_A4 and LSAVE_A5. Since those offsets are relative to the original pt_regs base, loading them after changing sp fetches the wrong slots. As a result, traced syscalls that use the 5th or 6th argument may receive corrupted arguments. This is visible with mmap2(), which takes six arguments. A small PTRACE_SYSCALL reproducer opens a file and maps one page with: mmap(NULL, 4096, PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0) Before the fix, the traced child fails the mmap and exits with 12. After the fix, the mapping succeeds and the child exits with 0. Fix the trace path by loading a4/a5 from pt_regs before changing sp. Tested on: ck860f, linux-4.19.15, C-SKY abiv2
References
- https://git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f
- https://git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de
- https://git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c
- https://git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d
- https://git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904
- https://git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8
- https://git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e
- https://git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263
FAQ
What is CVE-2026-93167?
CVE-2026-93167 is a documented vulnerability. In the Linux kernel, the following vulnerability has been resolved: csky: Fix a4/a5 restoration in syscall trace path The syscall trace path reloads syscall arguments from pt_regs before calling the...
How severe is CVE-2026-93167?
CVSS scoring is not yet available for CVE-2026-93167. Check NVD for updates.
Is there a patch for CVE-2026-93167?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.