{"api_version":"1","generated_at":"2026-09-23T03:42:30+00:00","cve":"CVE-2026-93167","urls":{"html":"https://cve.report/CVE-2026-93167","api":"https://cve.report/api/cve/CVE-2026-93167.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-93167","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-93167"},"summary":{"title":"csky: Fix a4/a5 restoration in syscall trace path","description":"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","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-17 17:18:12","updated_at":"2026-09-17 17:18:12"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d","name":"https://git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904","name":"https://git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f","name":"https://git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de","name":"https://git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c","name":"https://git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e","name":"https://git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8","name":"https://git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263","name":"https://git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-93167","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93167","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 e9ae8e86eed68bea5d2670eadf61938a43bd2263 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 64e3ec7a71d3b715e2567f19f64207f04999bb0c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 863fa63fd1491f201ac819f805a8db98d2a32c3d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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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"}],"providerMetadata":{"dateUpdated":"2026-09-17T16:11:59.234Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263"},{"url":"https://git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c"},{"url":"https://git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d"},{"url":"https://git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e"},{"url":"https://git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f"},{"url":"https://git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904"},{"url":"https://git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de"},{"url":"https://git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8"}],"title":"csky: Fix a4/a5 restoration in syscall trace path","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-93167","datePublished":"2026-09-17T16:11:59.234Z","dateReserved":"2026-09-17T16:02:15.090Z","dateUpdated":"2026-09-17T16:11:59.234Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-17 17:18:12","lastModifiedDate":"2026-09-17 17:18:12","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"93167","Ordinal":"1","Title":"csky: Fix a4/a5 restoration in syscall trace path","CVE":"CVE-2026-93167","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"93167","Ordinal":"1","NoteData":"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","Type":"Description","Title":"csky: Fix a4/a5 restoration in syscall trace path"}]}}}