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FKIE_CVE-2026-93167

Vulnerability from fkie_nvd - Published: 2026-09-17 17:18 - Updated: 2026-09-17 17:18
Severity
Summary
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
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/csky/kernel/entry.S"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e9ae8e86eed68bea5d2670eadf61938a43bd2263",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "lessThan": "64e3ec7a71d3b715e2567f19f64207f04999bb0c",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "lessThan": "863fa63fd1491f201ac819f805a8db98d2a32c3d",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "lessThan": "e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "lessThan": "31c81b376e5f058c7f2c94f69719cf7caec2fc3f",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "lessThan": "a776afa89424570bfa637ebf812ca281a5732904",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "lessThan": "343aa5275484d627c921a42e8e115cae366be5de",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "lessThan": "abb81e5ce7d995baa41556b8125fa59e28ba3be8",
              "status": "affected",
              "version": "e0bbb53843b5fdfe464b099217e3b9d97e8a75d7",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "108681048cf728a8570e036c34ebd7daa43133b4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3a5837c692918c229baf63fe7950965d27c48ac2",
              "versionType": "git"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.47",
              "versionType": "semver"
            },
            {
              "lessThan": "5.7",
              "status": "affected",
              "version": "5.6.19",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/csky/kernel/entry.S"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncsky: Fix a4/a5 restoration in syscall trace path\n\nThe syscall trace path reloads syscall arguments from pt_regs before\ncalling the syscall handler. On C-SKY ABIv2, the 5th and 6th syscall\narguments are prepared as stack arguments before invoking syscallid.\n\nThe current code adjusts sp before loading LSAVE_A4 and LSAVE_A5. Since\nthose offsets are relative to the original pt_regs base, loading them\nafter changing sp fetches the wrong slots. As a result, traced syscalls\nthat use the 5th or 6th argument may receive corrupted arguments.\n\nThis is visible with mmap2(), which takes six arguments. A small\nPTRACE_SYSCALL reproducer opens a file and maps one page with:\n\n  mmap(NULL, 4096, PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0)\n\nBefore the fix, the traced child fails the mmap and exits with 12.\nAfter the fix, the mapping succeeds and the child exits with 0.\n\nFix the trace path by loading a4/a5 from pt_regs before changing sp.\n\nTested on: ck860f, linux-4.19.15, C-SKY abiv2"
    }
  ],
  "id": "CVE-2026-93167",
  "lastModified": "2026-09-17T17:18:12.243",
  "metrics": {},
  "published": "2026-09-17T17:18:12.243",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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