csky: Fix a4/a5 restoration in syscall trace path
Summary
| CVE | CVE-2026-93167 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-17 17:18:12 UTC |
| Updated | 2026-09-17 17:18:12 UTC |
| 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 |
Risk And Classification
EPSS: 0.002110000 probability, percentile 0.116640000 (date 2026-09-18)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 e9ae8e86eed68bea5d2670eadf61938a43bd2263 git | Not specified |
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 64e3ec7a71d3b715e2567f19f64207f04999bb0c git | Not specified |
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 863fa63fd1491f201ac819f805a8db98d2a32c3d git | Not specified |
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e git | Not specified |
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 31c81b376e5f058c7f2c94f69719cf7caec2fc3f git | Not specified |
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 a776afa89424570bfa637ebf812ca281a5732904 git | Not specified |
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 343aa5275484d627c921a42e8e115cae366be5de git | Not specified |
| CNA | Linux | Linux | affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 abb81e5ce7d995baa41556b8125fa59e28ba3be8 git | Not specified |
| CNA | Linux | Linux | affected 108681048cf728a8570e036c34ebd7daa43133b4 git | Not specified |
| CNA | Linux | Linux | affected 3a5837c692918c229baf63fe7950965d27c48ac2 git | Not specified |
| CNA | Linux | Linux | affected 5.4.47 5.5 semver | Not specified |
| CNA | Linux | Linux | affected 5.6.19 5.7 semver | Not specified |
| CNA | Linux | Linux | affected 5.7 | Not specified |
| CNA | Linux | Linux | unaffected 5.7 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.270 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.221 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.188 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.157 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.110 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.52 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.6 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.