{"id":"CVE-2026-93127","revision":"d4e3fbffaf1543b2a0a41d9b6fa3e67e","records":[{"revision":"d4e3fbffaf1543b2a0a41d9b6fa3e67e","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-93127","aliases":[],"title":"bpf: Drop scalar id on sign-extending narrowing stack fills","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Drop scalar id on sign-extending narrowing stack fills\n\nWhen a spilled scalar is filled back with a sign-extending narrowing load\n(BPF_MEMSX), check_stack_read_fixed_off() copies the spilled register\nincluding its scalar id, but coerce_reg_to_size_sx() then sign-extends the\nfilled register's value. If the same slot is also filled with a plain\nzero-extending load (BPF_MEM), both destination registers share the id yet\nhold different values. A later 'if <zext-reg> == const' then refines the\nsign-extended register through sync_linked_regs() to a value it does not\nhave at runtime (e.g. the verifier believes 0x80000000 while the register\nis 0xffffffff80000000), which can be turned into an out-of-bounds access.\n\nDrop the shared scalar id at the sign-extension site in check_mem_access()\nwhen sign extension actually changes the value, mirroring the BPF_MOVSX\nhandling in check_alu_op() (no_sext = reg_umax < 2^(size*8-1)).","state":0,"publishedAt":"2026-09-17T16:11:31.253+00:00","modifiedAt":"2026-10-19T09:06:00.545+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                        \"kernel/bpf/verifier.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3cd5c890652ba1f0682adc291b5446245259b692\",\n                            \"lessThan\": \"f3614622dc41f3dd99bb4f691da253814e4e6cae\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3cd5c890652ba1f0682adc291b5446245259b692\",\n                            \"lessThan\": \"2cb5f4ca695ebe552647e5ba4aad6934d6a43bae\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\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                        \"kernel/bpf/verifier.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7.0\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"7.0\",\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":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/f3614622dc41f3dd99bb4f691da253814e4e6cae","https://git.kernel.org/stable/c/2cb5f4ca695ebe552647e5ba4aad6934d6a43bae"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93127","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-93127","identifiers":["CVE-2026-93127"]},"retained":false,"historicalAffected":[]}],"coverage":[]}