{"id":"CVE-2026-93167","revision":"ca204941b1c24df792905c2bbb598ee1","records":[{"revision":"ca204941b1c24df792905c2bbb598ee1","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-93167","aliases":[],"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":0,"publishedAt":"2026-09-17T16:11:59.234+00:00","modifiedAt":"2026-10-19T09:06:39.063+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/csky/kernel/entry.S\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"e9ae8e86eed68bea5d2670eadf61938a43bd2263\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"64e3ec7a71d3b715e2567f19f64207f04999bb0c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"863fa63fd1491f201ac819f805a8db98d2a32c3d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"31c81b376e5f058c7f2c94f69719cf7caec2fc3f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"a776afa89424570bfa637ebf812ca281a5732904\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"343aa5275484d627c921a42e8e115cae366be5de\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"e0bbb53843b5fdfe464b099217e3b9d97e8a75d7\",\n                            \"lessThan\": \"abb81e5ce7d995baa41556b8125fa59e28ba3be8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"108681048cf728a8570e036c34ebd7daa43133b4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3a5837c692918c229baf63fe7950965d27c48ac2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.4.47\",\n                            \"lessThan\": \"5.5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.6.19\",\n                            \"lessThan\": \"5.7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/csky/kernel/entry.S\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.7\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.7\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.110\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.52\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.6\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/e9ae8e86eed68bea5d2670eadf61938a43bd2263","https://git.kernel.org/stable/c/64e3ec7a71d3b715e2567f19f64207f04999bb0c","https://git.kernel.org/stable/c/863fa63fd1491f201ac819f805a8db98d2a32c3d","https://git.kernel.org/stable/c/e71a3dc5b8d2ea4d9cfbdb135d6b7777de84212e","https://git.kernel.org/stable/c/31c81b376e5f058c7f2c94f69719cf7caec2fc3f","https://git.kernel.org/stable/c/a776afa89424570bfa637ebf812ca281a5732904","https://git.kernel.org/stable/c/343aa5275484d627c921a42e8e115cae366be5de","https://git.kernel.org/stable/c/abb81e5ce7d995baa41556b8125fa59e28ba3be8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93167","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-93167","identifiers":["CVE-2026-93167"]},"retained":false,"historicalAffected":[]}],"coverage":[]}