{"id":"CVE-2026-90359","title":"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 tra…","summary":"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 tra…","severity":"high","vendor":"Linux","product":"Linux","affected":["Linux >= fec56f5890d93fc2ed74166c397dc186b1c25951 < d36ac53fc83baf843c51b7afd6d2471f36b713d8","Linux >= fec56f5890d93fc2ed74166c397dc186b1c25951 < c48796aa6c392cde93946e5d5a9a1f1b1cf72feb","Linux 5.5"],"published":"2026-09-17","updated":"2026-10-15","sourceUpdated":"2026-10-15T11:18:01.910","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90359","references":[{"url":"https://git.kernel.org/stable/c/9a9e902bd0556052534641f7d5f868c6dc4b84ae","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c48796aa6c392cde93946e5d5a9a1f1b1cf72feb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d36ac53fc83baf843c51b7afd6d2471f36b713d8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90359.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-90359"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536539"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-90359"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90359"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90359.mbox"},{"url":"https://kernelcve.org/list/?q=CVE-2026-90359"},{"url":"https://git.kernel.org/stable/c/de54ba33690d2dd3c4aa686c9693505644285b0b"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00209,"epssPercentile":0.10961,"ingestedAt":"2026-09-17T16:21:47.812Z","cvss":7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"vendor","cwe":["CWE-805","CWE-20"],"slug":"CVE-2026-90359","body":"## Overview\n\nIn 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().\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90359.json)","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":225637,"id":"CVE-2026-90359","ts":1792498327659,"field":"cvss","old":null,"new":"7"},{"seq":225636,"id":"CVE-2026-90359","ts":1792498327659,"field":"severity","old":"none","new":"high"}]}