{"id":"CVE-2026-90195","state":"PUBLISHED","title":"riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args","description":"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 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.","publishedAt":"2026-09-17T16:07:14.979Z","updatedAt":"2026-10-19T08:59:31.672Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"555fc6f1caf00ce7005e732b688da26c0dc3c5c5","versionType":"git"},{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"801ae90f8ce099187e6224cec7d72d07a4df0324","versionType":"git"},{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"71dbd143be598954ae103feadd12692aeb0f2f88","versionType":"git"},{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"f2aaa621591093cfe8224a25ef2f04a3b1e304b0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/net/bpf_jit_comp64.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/net/bpf_jit_comp64.c"]}],"references":["https://git.kernel.org/stable/c/555fc6f1caf00ce7005e732b688da26c0dc3c5c5","https://git.kernel.org/stable/c/801ae90f8ce099187e6224cec7d72d07a4df0324","https://git.kernel.org/stable/c/71dbd143be598954ae103feadd12692aeb0f2f88","https://git.kernel.org/stable/c/f2aaa621591093cfe8224a25ef2f04a3b1e304b0"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90195.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90195","state":"PUBLISHED","datePublished":"2026-09-17T16:07:14.979Z","dateUpdated":"2026-10-19T08:59:31.672Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.792Z"},"containers":{"cna":{"title":"riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args","descriptions":[{"lang":"en","value":"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 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"555fc6f1caf00ce7005e732b688da26c0dc3c5c5","versionType":"git"},{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"801ae90f8ce099187e6224cec7d72d07a4df0324","versionType":"git"},{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"71dbd143be598954ae103feadd12692aeb0f2f88","versionType":"git"},{"version":"443574b033876c85a35de4c65c14f7fe092222b2","status":"affected","lessThan":"f2aaa621591093cfe8224a25ef2f04a3b1e304b0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/net/bpf_jit_comp64.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/net/bpf_jit_comp64.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/555fc6f1caf00ce7005e732b688da26c0dc3c5c5"},{"url":"https://git.kernel.org/stable/c/801ae90f8ce099187e6224cec7d72d07a4df0324"},{"url":"https://git.kernel.org/stable/c/71dbd143be598954ae103feadd12692aeb0f2f88"},{"url":"https://git.kernel.org/stable/c/f2aaa621591093cfe8224a25ef2f04a3b1e304b0"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:59:31.672Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}