CVE-2026-90195 (GCVE-0-2026-90195)
Vulnerability from cvelistv5
Published
2026-09-17 16:07
Modified
2026-10-19 08:59
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args On RV64, the ABI requires sign-extension for signed 1-byte and 2-byte kfunc args. However, the RV64 JIT currently does not perform sign-extension for such kfunc args. Before commit 7ce090afbf72 ("bpf: Infer zext_dst based on static register liveness analysis"), state pruning could potentially omit zero-extension of 32-bit subregisters, which inadvertently masked the above issue by making the args appear as if they had been properly sign-extended. After that commit, the problem is exposed, causing the kfunc_call/kfunc_call_test4 selftest to fail. Fix this by extending the existing sign-extension logic to handle signed 1-byte and 2-byte kfunc args as well.
References
Impacted products
Vendor Product Version
Linux Linux Version: 443574b033876c85a35de4c65c14f7fe092222b2
Version: 443574b033876c85a35de4c65c14f7fe092222b2
Version: 443574b033876c85a35de4c65c14f7fe092222b2
Version: 443574b033876c85a35de4c65c14f7fe092222b2
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/riscv/net/bpf_jit_comp64.c"
          ],
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          "vendor": "Linux",
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              "version": "0",
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              "status": "unaffected",
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              "versionType": "semver"
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      "cpeApplicability": [
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              ],
              "negate": false,
              "operator": "OR"
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        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:59:31.672Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "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"
        }
      ],
      "title": "riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args",
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90195",
    "datePublished": "2026-09-17T16:07:14.979Z",
    "dateReserved": "2026-09-11T19:38:34.792Z",
    "dateUpdated": "2026-10-19T08:59:31.672Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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