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CVE-2026-90195

Status: ReceivedUnscored—

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.

Read full descriptionShow less

Fix this by extending the existing sign-extension logic to handle signed 1-byte and 2-byte kfunc args as well.

CVSS

NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux KernelAI

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-90195",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "443574b033876c85a35de4c65c14f7fe092222b2",
              "lessThan": "555fc6f1caf00ce7005e732b688da26c0dc3c5c5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "443574b033876c85a35de4c65c14f7fe092222b2",
              "lessThan": "801ae90f8ce099187e6224cec7d72d07a4df0324",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "443574b033876c85a35de4c65c14f7fe092222b2",
              "lessThan": "71dbd143be598954ae103feadd12692aeb0f2f88",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "443574b033876c85a35de4c65c14f7fe092222b2",
              "lessThan": "f2aaa621591093cfe8224a25ef2f04a3b1e304b0",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/riscv/net/bpf_jit_comp64.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.9",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/riscv/net/bpf_jit_comp64.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-17T17:17:14.280",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/555fc6f1caf00ce7005e732b688da26c0dc3c5c5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/71dbd143be598954ae103feadd12692aeb0f2f88",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/801ae90f8ce099187e6224cec7d72d07a4df0324",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f2aaa621591093cfe8224a25ef2f04a3b1e304b0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "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."
    }
  ],
  "lastModified": "2026-09-17T17:17:14.280",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}