CVE-2026-98403 (GCVE-0-2026-98403)

Vulnerability from cvelistv5 – Published: 2026-10-14 13:26 – Updated: 2026-10-19 09:18
VLAI
Title
s390/boot: Avoid IPL parameter append past command line
Summary
In the Linux kernel, the following vulnerability has been resolved: s390/boot: Avoid IPL parameter append past command line A command line may occupy all but the terminating byte of COMMAND_LINE_SIZE. In that case append_ipl_block_parm() passes a zero size to the IPL parameter conversion helpers and points the destination one byte past early_command_line. The helpers subtract one from the unsigned size and write the converted parameter outside the command line buffer. Convert the IPL parameter in the command line parsing buffer first. A parameter beginning with '=' can then replace the existing command line regardless of its length, while other parameters are appended only when space remains.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6843 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 , < af9866021a00ab9eeacf0c33ee73f3d134b4ed70 (git)
Affected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 , < 73eec5a0d55916d7e1115f5d03a7ffc06d6215cf (git)
Affected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 , < 8d11bfec8666f8409fac9072e9c25b691d3e30ac (git)
Affected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 , < d76181dfabdaa720703167393704efacba343442 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.16
Unaffected: 0 , < 5.16 (semver)
Unaffected: 6.12.112 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/boot/ipl_parm.c"
          ],
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              "negate": false,
              "operator": "OR"
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/boot: Avoid IPL parameter append past command line\n\nA command line may occupy all but the terminating byte of\nCOMMAND_LINE_SIZE. In that case append_ipl_block_parm() passes a zero size\nto the IPL parameter conversion helpers and points the destination one\nbyte past early_command_line. The helpers subtract one from the unsigned\nsize and write the converted parameter outside the command line buffer.\n\nConvert the IPL parameter in the command line parsing buffer first. A\nparameter beginning with \u0027=\u0027 can then replace the existing command line\nregardless of its length, while other parameters are appended only when\nspace remains."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:18:56.682Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "title": "s390/boot: Avoid IPL parameter append past command line",
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    "datePublished": "2026-10-14T13:26:02.916Z",
    "dateReserved": "2026-09-25T10:25:14.347Z",
    "dateUpdated": "2026-10-19T09:18:56.682Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-10-22",
      "epss": "0.00209",
      "percentile": "0.10532"
    },
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      "cve": "CVE-2026-98403",
      "id": "msrc_CVE-2026-98403",
      "initial_release_date": "2026-10-16T01:03:26.000Z",
      "product_status:known_not_affected": "1",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "s390/boot: Avoid IPL parameter append past command line",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-98403.json",
      "version": "2"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/boot: Avoid IPL parameter append past command line\n\nA command line may occupy all but the terminating byte of\nCOMMAND_LINE_SIZE. In that case append_ipl_block_parm() passes a zero size\nto the IPL parameter conversion helpers and points the destination one\nbyte past early_command_line. The helpers subtract one from the unsigned\nsize and write the converted parameter outside the command line buffer.\n\nConvert the IPL parameter in the command line parsing buffer first. A\nparameter beginning with \u0027=\u0027 can then replace the existing command line\nregardless of its length, while other parameters are appended only when\nspace remains."
          }
        ],
        "id": "CVE-2026-98403",
        "lastModified": "2026-10-19T10:18:45.243",
        "metrics": {},
        "published": "2026-10-14T14:17:51.383",
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    }
  }
}



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