{
  "threat_severity" : "Moderate",
  "public_date" : "2026-03-18T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: Linux kernel: Denial of service and memory corruption in RDMA umad",
    "id" : "2448594",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2448594"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.3",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-131",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nRDMA/umad: Reject negative data_len in ib_umad_write\nib_umad_write computes data_len from user-controlled count and the\nMAD header sizes. With a mismatched user MAD header size and RMPP\nheader length, data_len can become negative and reach ib_create_send_mad().\nThis can make the padding calculation exceed the segment size and trigger\nan out-of-bounds memset in alloc_send_rmpp_list().\nAdd an explicit check to reject negative data_len before creating the\nsend buffer.\nKASAN splat:\n[  211.363464] BUG: KASAN: slab-out-of-bounds in ib_create_send_mad+0xa01/0x11b0\n[  211.364077] Write of size 220 at addr ffff88800c3fa1f8 by task spray_thread/102\n[  211.365867] ib_create_send_mad+0xa01/0x11b0\n[  211.365887] ib_umad_write+0x853/0x1c80", "A flaw was found in the Linux kernel's Remote Direct Memory Access (RDMA) `umad` (User Mode Access Device) component. A local user can exploit this vulnerability by manipulating input, causing an integer underflow that leads to an out-of-bounds memory write. This memory corruption can result in a denial of service (DoS) by crashing the system, and may also lead to limited information disclosure or data integrity issues." ],
  "statement" : "This bug is a kernel out-of-bounds write in the RDMA umad write path caused by a user-controlled length calculation that could underflow and pass an invalid data_len into MAD send buffer creation.\nA local user with access to the umad interface can trigger the issue by supplying mismatched MAD and RMPP header sizes, which leads to an out-of-bounds memset in the send MAD allocation path and can corrupt kernel memory.",
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Under investigation",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-23243\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-23243\nhttps://lore.kernel.org/linux-cve-announce/2026031816-CVE-2026-23243-b88e@gregkh/T" ],
  "name" : "CVE-2026-23243",
  "mitigation" : {
    "value" : "To mitigate this issue, prevent module ib_umad from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.",
    "lang" : "en:us"
  },
  "csaw" : false
}