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CVE-2025-21993 (GCVE-0-2025-21993)

Vulnerability from cvelistv5 – Published: 2025-04-02 12:53 – Updated: 2026-05-11 21:10
VLAI
Title
iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic()
Summary
In the Linux kernel, the following vulnerability has been resolved: iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic() When performing an iSCSI boot using IPv6, iscsistart still reads the /sys/firmware/ibft/ethernetX/subnet-mask entry. Since the IPv6 prefix length is 64, this causes the shift exponent to become negative, triggering a UBSAN warning. As the concept of a subnet mask does not apply to IPv6, the value is set to ~0 to suppress the warning message.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-10-01 17:13 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < a858cd58dea06cf85b142673deea8c5d87f11e70 (git)
Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < f763c82db8166e28f45b7cc4a5398a7859665940 (git)
Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < b388e185bfad32bfed6a97a6817f74ca00a4318f (git)
Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < 9bfa80c8aa4e06dff55a953c3fffbfc68a3a3b1c (git)
Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < 2d1eef248107bdf3d5a69d0fde04c30a79a7bf5d (git)
Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < b253660fac5e0e9080d2c95e3a029e1898d49afb (git)
Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < c1c6e527470e5eab0b2d57bd073530fbace39eab (git)
Affected: 138fe4e069798d9aa948a5402ff15e58f483ee4e , < 07e0d99a2f701123ad3104c0f1a1e66bce74d6e5 (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.26
Unaffected: 0 , < 2.6.26 (semver)
Unaffected: 5.4.292 , ≤ 5.4.* (semver)
Unaffected: 5.10.236 , ≤ 5.10.* (semver)
Unaffected: 5.15.180 , ≤ 5.15.* (semver)
Unaffected: 6.1.132 , ≤ 6.1.* (semver)
Unaffected: 6.6.84 , ≤ 6.6.* (semver)
Unaffected: 6.12.20 , ≤ 6.12.* (semver)
Unaffected: 6.13.8 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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      "initial_release_date": "2025-04-02T00:00:00+00:00",
      "product_status:fixed": "612",
      "product_status:known_affected": "112",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21993.json",
      "version": "3"
    },
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      "current_release_date": "2026-08-29T01:25:49Z",
      "cve": "CVE-2025-21993",
      "id": "CVE-2025-21993",
      "initial_release_date": "2025-04-03T01:03:49Z",
      "product_status:known_affected": "765",
      "product_status:recommended": "467",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-21993",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-21993.json",
      "version": "52"
    },
    "vulnrichment": {
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              "dateUpdated": "2025-11-03T19:40:33.731Z",
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            ],
            "title": "CVE Program Container"
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              "versions": [
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              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic()\n\nWhen performing an iSCSI boot using IPv6, iscsistart still reads the\n/sys/firmware/ibft/ethernetX/subnet-mask entry. Since the IPv6 prefix\nlength is 64, this causes the shift exponent to become negative,\ntriggering a UBSAN warning. As the concept of a subnet mask does not\napply to IPv6, the value is set to ~0 to suppress the warning message."
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          "title": "iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic()",
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        "assignerShortName": "Linux",
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        "datePublished": "2025-04-02T12:53:15.513Z",
        "dateReserved": "2024-12-29T08:45:45.801Z",
        "dateUpdated": "2026-01-02T15:28:44.546Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
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    }
  }
}



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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.