FKIE_CVE-2026-90011

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-10-19 09:18
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Reserve a terminator byte for the login payload iscsi_target_check_login_request() rejects a login PDU whose DataSegmentLength exceeds MAX_KEY_VALUE_PAIRS, but the test is '>' and login->req_buf is allocated with exactly MAX_KEY_VALUE_PAIRS bytes. Since iscsit_get_login_rx() receives payload_length + padding bytes, where padding = ((-payload_length) & 3); any payload_length from 8189 to 8192 fills the whole 8192 byte buffer. The write stays in bounds, but no byte is left for a NUL terminator. The buffer is subsequently consumed as a C string. In the CHAP path chap_check_algorithm() calls kstrdup(a_str), and extract_param() calls strstr(in_buf, pattern) followed by strlen_semi(), none of which take a length. convert_null_to_semi() additionally rewrites every embedded NUL to ';', so even a payload made of well formed NUL separated key=value records is left without a terminator. These walk past the end of the object into adjacent slab memory. It is reachable by an unauthenticated initiator against a portal configured for CHAP; when authentication is not required iscsi_login_zero_tsih_s2() rewrites AuthMethod to None and the CHAP path is never entered. Allocate one extra byte. kzalloc() zeroes it and nothing ever writes to it, as every writer copies to offset 0 for at most MAX_KEY_VALUE_PAIRS bytes, so the buffer is always terminated.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1624bff4c5118ad494d50ad94d44f22064667a7f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3ddf3ea291a0ef2ea93b82e158960ac2cc42302b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5fac79f248c37774d1dd761406f83d25ca6ff8e4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6ddddcad436d8e6e619204d3c848147ff2f5bf1e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b19dc17ed963ac36c0db4b52a1803fb11169f91f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/eb9dadf4d552ebe10644871c5189286552aa48f5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f4825922d2fb371e2b969697d792077f1b62b62c
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/target/iscsi/iscsi_target_login.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5fac79f248c37774d1dd761406f83d25ca6ff8e4",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            },
            {
              "lessThan": "6ddddcad436d8e6e619204d3c848147ff2f5bf1e",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            },
            {
              "lessThan": "b19dc17ed963ac36c0db4b52a1803fb11169f91f",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            },
            {
              "lessThan": "6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            },
            {
              "lessThan": "eb9dadf4d552ebe10644871c5189286552aa48f5",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            },
            {
              "lessThan": "1624bff4c5118ad494d50ad94d44f22064667a7f",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            },
            {
              "lessThan": "3ddf3ea291a0ef2ea93b82e158960ac2cc42302b",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            },
            {
              "lessThan": "f4825922d2fb371e2b969697d792077f1b62b62c",
              "status": "affected",
              "version": "e48354ce078c079996f89d715dfa44814b4eba01",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/target/iscsi/iscsi_target_login.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.1"
            },
            {
              "lessThan": "3.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: iscsi: Reserve a terminator byte for the login payload\n\niscsi_target_check_login_request() rejects a login PDU whose\nDataSegmentLength exceeds MAX_KEY_VALUE_PAIRS, but the test is \u0027\u003e\u0027 and\nlogin-\u003ereq_buf is allocated with exactly MAX_KEY_VALUE_PAIRS\nbytes. Since iscsit_get_login_rx() receives payload_length + padding\nbytes, where\n\n\tpadding = ((-payload_length) \u0026 3);\n\nany payload_length from 8189 to 8192 fills the whole 8192 byte\nbuffer. The write stays in bounds, but no byte is left for a NUL\nterminator.\n\nThe buffer is subsequently consumed as a C string. In the CHAP path\nchap_check_algorithm() calls kstrdup(a_str), and extract_param() calls\nstrstr(in_buf, pattern) followed by strlen_semi(), none of which take a\nlength. convert_null_to_semi() additionally rewrites every embedded NUL\nto \u0027;\u0027, so even a payload made of well formed NUL separated key=value\nrecords is left without a terminator. These walk past the end of the\nobject into adjacent slab memory. It is reachable by an unauthenticated\ninitiator against a portal configured for CHAP; when authentication is\nnot required iscsi_login_zero_tsih_s2() rewrites AuthMethod to None and\nthe CHAP path is never entered.\n\nAllocate one extra byte. kzalloc() zeroes it and nothing ever writes to\nit, as every writer copies to offset 0 for at most MAX_KEY_VALUE_PAIRS\nbytes, so the buffer is always terminated."
    }
  ],
  "id": "CVE-2026-90011",
  "lastModified": "2026-10-19T09:18:48.927",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-16T11:17:13.760",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1624bff4c5118ad494d50ad94d44f22064667a7f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3ddf3ea291a0ef2ea93b82e158960ac2cc42302b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5fac79f248c37774d1dd761406f83d25ca6ff8e4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b589ef9d5f6cdc70d2b4f269ca6cf26b5ebb076"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6ddddcad436d8e6e619204d3c848147ff2f5bf1e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b19dc17ed963ac36c0db4b52a1803fb11169f91f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/eb9dadf4d552ebe10644871c5189286552aa48f5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f4825922d2fb371e2b969697d792077f1b62b62c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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