CVE-2026-31482 (GCVE-0-2026-31482)
Vulnerability from cvelistv5
Published
2026-04-22 13:54
Modified
2026-05-11 22:09
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: s390/entry: Scrub r12 register on kernel entry Before commit f33f2d4c7c80 ("s390/bp: remove TIF_ISOLATE_BP"), all entry handlers loaded r12 with the current task pointer (lg %r12,__LC_CURRENT) for use by the BPENTER/BPEXIT macros. That commit removed TIF_ISOLATE_BP, dropping both the branch prediction macros and the r12 load, but did not add r12 to the register clearing sequence. Add the missing xgr %r12,%r12 to make the register scrub consistent across all entry points.
References
Impacted products
Vendor Product Version
Linux Linux Version: f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780
Version: f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780
Version: f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780
Version: f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780
Version: f33f2d4c7c80c641f6ca3dfe5e7dfe1f91543780
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kernel/entry.S"
          ],
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        {
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.4"
            },
            {
              "lessThan": "6.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.12.80",
              "versionType": "semver"
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.131",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.80",
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                },
                {
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/entry: Scrub r12 register on kernel entry\n\nBefore commit f33f2d4c7c80 (\"s390/bp: remove TIF_ISOLATE_BP\"),\nall entry handlers loaded r12 with the current task pointer\n(lg %r12,__LC_CURRENT) for use by the BPENTER/BPEXIT macros. That\ncommit removed TIF_ISOLATE_BP, dropping both the branch prediction\nmacros and the r12 load, but did not add r12 to the register clearing\nsequence.\n\nAdd the missing xgr %r12,%r12 to make the register scrub consistent\nacross all entry points."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:09:35.182Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a58d298a83a3a9b7ca99ded9d60a1e77231159ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/95c899cd791803a5bf7b73e5994fbbe1cc1a9c36"
        },
        {
          "url": "https://git.kernel.org/stable/c/7f4e3233faa8470dd0627bc49b2809f2bfebd909"
        },
        {
          "url": "https://git.kernel.org/stable/c/99a8b420f3f0e162eb9c9c9253929d4d23f9bd30"
        },
        {
          "url": "https://git.kernel.org/stable/c/0738d395aab8fae3b5a3ad3fc640630c91693c27"
        }
      ],
      "title": "s390/entry: Scrub r12 register on kernel entry",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31482",
    "datePublished": "2026-04-22T13:54:08.888Z",
    "dateReserved": "2026-03-09T15:48:24.101Z",
    "dateUpdated": "2026-05-11T22:09:35.182Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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