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CVE-2026-43006 (GCVE-0-2026-43006)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-08-05 12:25
VLAI
Title
io_uring/rsrc: reject zero-length fixed buffer import
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: reject zero-length fixed buffer import validate_fixed_range() admits buf_addr at the exact end of the registered region when len is zero, because the check uses strict greater-than (buf_end > imu->ubuf + imu->len). io_import_fixed() then computes offset == imu->len, which causes the bvec skip logic to advance past the last bio_vec entry and read bv_offset from out-of-bounds slab memory. Return early from io_import_fixed() when len is zero. A zero-length import has no data to transfer and should not walk the bvec array at all. BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0 Read of size 4 at addr ffff888002bcc254 by task poc/103 Call Trace: io_import_reg_buf+0x697/0x7f0 io_write_fixed+0xd9/0x250 __io_issue_sqe+0xad/0x710 io_issue_sqe+0x7d/0x1100 io_submit_sqes+0x86a/0x23c0 __do_sys_io_uring_enter+0xa98/0x1590 Allocated by task 103: The buggy address is located 12 bytes to the right of allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 8622b20f23ed165f48b8ca61503a107d17f8d585 , < 040a1e7e0e2f01851fec1dd2d96906f8636a9f75 (git)
Affected: 8622b20f23ed165f48b8ca61503a107d17f8d585 , < 40170fc1a79c1b2e68f09ae6aac687b7305ae6f4 (git)
Affected: 8622b20f23ed165f48b8ca61503a107d17f8d585 , < 111a12b422a8cfa93deabaef26fec48237163214 (git)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/rsrc: reject zero-length fixed buffer import\n\nvalidate_fixed_range() admits buf_addr at the exact end of the\nregistered region when len is zero, because the check uses strict\ngreater-than (buf_end \u003e imu-\u003eubuf + imu-\u003elen).  io_import_fixed()\nthen computes offset == imu-\u003elen, which causes the bvec skip logic\nto advance past the last bio_vec entry and read bv_offset from\nout-of-bounds slab memory.\n\nReturn early from io_import_fixed() when len is zero.  A zero-length\nimport has no data to transfer and should not walk the bvec array\nat all.\n\n  BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0\n  Read of size 4 at addr ffff888002bcc254 by task poc/103\n  Call Trace:\n   io_import_reg_buf+0x697/0x7f0\n   io_write_fixed+0xd9/0x250\n   __io_issue_sqe+0xad/0x710\n   io_issue_sqe+0x7d/0x1100\n   io_submit_sqes+0x86a/0x23c0\n   __do_sys_io_uring_enter+0xa98/0x1590\n  Allocated by task 103:\n  The buggy address is located 12 bytes to the right of\n   allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)"
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              "value": "AV:L - The vulnerable path is reached through local io_uring syscalls: create a ring, register a fixed buffer, then submit READ_FIXED or WRITE_FIXED. It is not reachable by remote packets or adjacent/physical input.\nAC:L - The trigger is deterministic: use len zero with buf_addr exactly at the end of a registered fixed buffer. No race or attacker-uncontrolled heap state is required to reach the out-of-bounds read.\nPR:L - An unprivileged local user can use io_uring when the upstream sysctl allows it, and buffer registration only requires ordinary user memory within resource limits. No real root or init-namespace capability is required.\nUI:N - After obtaining local execution, the attacker directly invokes io_uring_setup, io_uring_register, and io_uring_enter. No victim action is needed.\nS:U - The vulnerability is in the kernel servicing the attacker\u0027s local process and does not cross a separate security authority such as a VM host boundary. Standard local kernel compromise or crash remains Scope Unchanged.\nC:H - The bug performs an attacker-triggered out-of-bounds read from adjacent kernel slab memory while constructing the fixed-buffer bio_vec iterator. Under conservative kernel scoring, this is treated as high confidentiality impact because kernel heap data is read outside the valid object.\nI:N - The demonstrated primitive is an out-of-bounds read of bio_vec metadata, not an out-of-bounds write or use-after-free. I did not find a defensible direct data modification or control-flow overwrite primitive from this zero-length import.\nA:H - The reported path produces a KASAN slab-out-of-bounds BUG in io_import_reg_buf, and the same local trigger can be submitted repeatedly. Kernel oops/panic potential is High availability impact."
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    "cveId": "CVE-2026-43006",
    "datePublished": "2026-05-01T14:15:14.176Z",
    "dateReserved": "2026-05-01T14:12:55.974Z",
    "dateUpdated": "2026-08-05T12:25:13.184Z",
    "state": "PUBLISHED"
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A zero-length\\nimport has no data to transfer and should not walk the bvec array\\nat all.\\n\\n  BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0\\n  Read of size 4 at addr ffff888002bcc254 by task poc/103\\n  Call Trace:\\n   io_import_reg_buf+0x697/0x7f0\\n   io_write_fixed+0xd9/0x250\\n   __io_issue_sqe+0xad/0x710\\n   io_issue_sqe+0x7d/0x1100\\n   io_submit_sqes+0x86a/0x23c0\\n   __do_sys_io_uring_enter+0xa98/0x1590\\n  Allocated by task 103:\\n  The buggy address is located 12 bytes to the right of\\n   allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"io_uring/rsrc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"8622b20f23ed165f48b8ca61503a107d17f8d585\",\"lessThan\":\"040a1e7e0e2f01851fec1dd2d96906f8636a9f75\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8622b20f23ed165f48b8ca61503a107d17f8d585\",\"lessThan\":\"40170fc1a79c1b2e68f09ae6aac687b7305ae6f4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8622b20f23ed165f48b8ca61503a107d17f8d585\",\"lessThan\":\"111a12b422a8cfa93deabaef26fec48237163214\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"io_uring/rsrc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.15\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.15\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.22\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.19.12\",\"lessThanOrEqual\":\"6.19.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H\",\"baseScore\":7.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.2}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-125\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.15\",\"versionEndExcluding\":\"6.18.22\",\"matchCriteriaId\":\"A0B69104-1744-49F9-BFD7-533364994A3E\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.19\",\"versionEndExcluding\":\"6.19.12\",\"matchCriteriaId\":\"0A2B9540-02D5-41B4-B16A-82AF66FD4F36\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"F253B622-8837-4245-BCE5-A7BF8FC76A16\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"F666C8D8-6538-46D4-B318-87610DE64C34\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"02259FDA-961B-47BC-AE7F-93D7EC6E90C2\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*\",\"matchCriteriaId\":\"58A9FEFF-C040-420D-8F0A-BFDAAA1DF258\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*\",\"matchCriteriaId\":\"1D2315C0-D46F-4F85-9754-F9E5E11374A6\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/040a1e7e0e2f01851fec1dd2d96906f8636a9f75\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/111a12b422a8cfa93deabaef26fec48237163214\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/40170fc1a79c1b2e68f09ae6aac687b7305ae6f4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-02T12:53:32+00:00",
      "cve": "CVE-2026-43006",
      "id": "CVE-2026-43006",
      "initial_release_date": "2026-05-01T00:00:00+00:00",
      "product_status:fixed": "309",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: io_uring/rsrc: reject zero-length fixed buffer import",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43006.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-06T01:22:12Z",
      "cve": "CVE-2026-43006",
      "id": "CVE-2026-43006",
      "initial_release_date": "2026-05-06T01:41:33Z",
      "product_status:known_not_affected": "291",
      "product_status:recommended": "42",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-43006",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-43006.json",
      "version": "3"
    }
  }
}



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  • 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.
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  • 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.


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