{"id":"CVE-2026-90359","revision":"ecef9f3f5bb74e1d83cb40bb2f77aef6","records":[{"revision":"ecef9f3f5bb74e1d83cb40bb2f77aef6","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-90359","aliases":[],"title":"bpf: Reject >8 byte return values on return-reading trampoline paths","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject >8 byte return values on return-reading trampoline paths\n\nbtf_distill_func_proto() builds the function model used for the\nfentry/fexit/fmod_ret/fsession trampolines and struct_ops. It has\naccepted a 16-byte __int128 return value since the trampoline was\nintroduced: __get_type_size() returns the integer's type size, and the\nreturn-type check only rejected ret < 0.\n\nBut the BPF trampoline preserves only 8 bytes of the return value (RAX on\nx86, i.e. R0). For an attach type that reads the target's return value the\nsecond half (RDX / R3) is neither saved nor restored, so a program\nattached to a function returning a 16-byte value corrupts the value seen\nby the real caller and itself observes only half of it. struct_ops\ntrampolines have the same limitation.\n\nThis affects the attach types that read the target's return value: fexit,\nfmod_ret and fsession (plus the _multi variants of fexit and fsession),\nand struct_ops. fentry/fentry_multi run before the target returns and are\nunaffected.\n\nReject a >8 byte return value for these attach types in\nbpf_check_attach_target() and bpf_check_attach_btf_id_multi(), and for\nstruct_ops in bpf_struct_ops_desc_init().","state":0,"publishedAt":"2026-09-17T16:09:04.187+00:00","modifiedAt":"2026-10-21T12:51:16.798+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/bpf_struct_ops.c\",\n                        \"kernel/bpf/verifier.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"fec56f5890d93fc2ed74166c397dc186b1c25951\",\n                            \"lessThan\": \"de54ba33690d2dd3c4aa686c9693505644285b0b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fec56f5890d93fc2ed74166c397dc186b1c25951\",\n                            \"lessThan\": \"9a9e902bd0556052534641f7d5f868c6dc4b84ae\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fec56f5890d93fc2ed74166c397dc186b1c25951\",\n                            \"lessThan\": \"d36ac53fc83baf843c51b7afd6d2471f36b713d8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fec56f5890d93fc2ed74166c397dc186b1c25951\",\n                            \"lessThan\": \"c48796aa6c392cde93946e5d5a9a1f1b1cf72feb\",\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/bpf_struct_ops.c\",\n                        \"kernel/bpf/verifier.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.5\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.5\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.114\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.57\",\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/de54ba33690d2dd3c4aa686c9693505644285b0b","https://git.kernel.org/stable/c/9a9e902bd0556052534641f7d5f868c6dc4b84ae","https://git.kernel.org/stable/c/d36ac53fc83baf843c51b7afd6d2471f36b713d8","https://git.kernel.org/stable/c/c48796aa6c392cde93946e5d5a9a1f1b1cf72feb"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-90359","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-90359","identifiers":["CVE-2026-90359"]},"retained":false,"historicalAffected":[]}],"coverage":[]}