{"id":"CVE-2026-90195","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args\n\nOn RV64, the ABI requires sign-extension for signed 1-byte and 2-byte kfunc\nargs","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args\n\nOn RV64, the ABI requires sign-extension for signed 1-byte and 2-byte kfunc\nargs. However, the…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 443574b033876c85a35de4c65c14f7fe092222b2 < 555fc6f1caf00ce7005e732b688da26c0dc3c5c5","Linux >= 443574b033876c85a35de4c65c14f7fe092222b2 < 801ae90f8ce099187e6224cec7d72d07a4df0324","Linux >= 443574b033876c85a35de4c65c14f7fe092222b2 < 71dbd143be598954ae103feadd12692aeb0f2f88","Linux >= 443574b033876c85a35de4c65c14f7fe092222b2 < f2aaa621591093cfe8224a25ef2f04a3b1e304b0","Linux 6.9"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:14.280","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90195","references":[{"url":"https://git.kernel.org/stable/c/555fc6f1caf00ce7005e732b688da26c0dc3c5c5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/71dbd143be598954ae103feadd12692aeb0f2f88","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/801ae90f8ce099187e6224cec7d72d07a4df0324","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f2aaa621591093cfe8224a25ef2f04a3b1e304b0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.862Z","epss":0.002,"epssPercentile":0.1011,"slug":"CVE-2026-90195","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nriscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args\n\nOn RV64, the ABI requires sign-extension for signed 1-byte and 2-byte kfunc\nargs. However, the RV64 JIT currently does not perform sign-extension for\nsuch kfunc args.\n\nBefore commit 7ce090afbf72 (\"bpf: Infer zext_dst based on static register\nliveness analysis\"), state pruning could potentially omit zero-extension\nof 32-bit subregisters, which inadvertently masked the above issue by making\nthe args appear as if they had been properly sign-extended. After that\ncommit, the problem is exposed, causing the kfunc_call/kfunc_call_test4\nselftest to fail.\n\nFix this by extending the existing sign-extension logic to handle signed\n1-byte and 2-byte kfunc args as well.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}