GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

FKIE_CVE-2026-90011

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-09-16 15:18
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-rc2",
              "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": "2026-09-16T15:18:24.763",
  "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"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.