# CVE-2026-93167: linux: In the Linux kernel, the following vulnerability has been resolved:  csky: Fix a4/a5 restoration in syscall trace pat...

CVE-2026-93167 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-93167, released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-93167
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026

## 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

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.190-1 | [DEBIAN-CVE-2026-93167](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93167.md) | Sep 23, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-93167](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93167.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-93167](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93167.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-93167](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93167.md) | Sep 23, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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