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

CVE-2026-89486 (GCVE-0-2026-89486)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-09-13 06:29
VLAI
Title
ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()
Summary
In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user() Commit 9e91f8a6c868 ("ipmi:msghandler: Remove srcu for the ipmi_interfaces list") dropped the synchronize_rcu() between unlinking the command receivers from intf->cmd_rcvrs and freeing them, updating only the comment that explains why the barrier is needed. The cmd_rcvrs list is still traversed under plain RCU: find_cmd_rcvr() walks it inside rcu_read_lock(), and handle_ipmb_get_msg_cmd() borrows rcvr->user from that lookup within the same read-side section. Without the grace period, _ipmi_destroy_user() can kfree() a cmd_rcvr while a reader still holds a pointer to it, causing a use-after-free. The rework only made srcu unnecessary for the interfaces list; the cmd_rcvrs list still relies on plain RCU. Restore the synchronize_rcu() before freeing the receivers.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 9e91f8a6c8688e27f4ccce7db457da87d6458836 , < 3088e41292fecf132f85f79af5ee4d620b9ff1b4 (git)
Affected: 9e91f8a6c8688e27f4ccce7db457da87d6458836 , < 5dc0b2a9af95a97861c1bffaf1687a3173e395c5 (git)
Affected: 9e91f8a6c8688e27f4ccce7db457da87d6458836 , < 05ec76cfbce653e07cec19b9b8b20e33449d5d87 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/char/ipmi/ipmi_msghandler.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3088e41292fecf132f85f79af5ee4d620b9ff1b4",
              "status": "affected",
              "version": "9e91f8a6c8688e27f4ccce7db457da87d6458836",
              "versionType": "git"
            },
            {
              "lessThan": "5dc0b2a9af95a97861c1bffaf1687a3173e395c5",
              "status": "affected",
              "version": "9e91f8a6c8688e27f4ccce7db457da87d6458836",
              "versionType": "git"
            },
            {
              "lessThan": "05ec76cfbce653e07cec19b9b8b20e33449d5d87",
              "status": "affected",
              "version": "9e91f8a6c8688e27f4ccce7db457da87d6458836",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/char/ipmi/ipmi_msghandler.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.50",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()\n\nCommit 9e91f8a6c868 (\"ipmi:msghandler: Remove srcu for the\nipmi_interfaces list\") dropped the synchronize_rcu() between unlinking\nthe command receivers from intf-\u003ecmd_rcvrs and freeing them, updating\nonly the comment that explains why the barrier is needed.\n\nThe cmd_rcvrs list is still traversed under plain RCU: find_cmd_rcvr()\nwalks it inside rcu_read_lock(), and handle_ipmb_get_msg_cmd() borrows\nrcvr-\u003euser from that lookup within the same read-side section. Without\nthe grace period, _ipmi_destroy_user() can kfree() a cmd_rcvr while a\nreader still holds a pointer to it, causing a use-after-free.\n\nThe rework only made srcu unnecessary for the interfaces list; the\ncmd_rcvrs list still relies on plain RCU. Restore the synchronize_rcu()\nbefore freeing the receivers."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached by close/release on /dev/ipmiN (ipmi_release \u2192 ipmi_destroy_user \u2192 _ipmi_destroy_user) after IPMICTL_REGISTER_FOR_CMD; BMC GET_MSG/IPMB/LAN command delivery is the RCU reader, not Linux network-packet processing, so the attack remains local like other /dev/ipmiN IPMI bugs.\nAC:L - The attacker controls the free side (open, register-for-cmd, close) and arms command watching, then races close against GET_MSG/IPMB/LAN command handling they can induce via their own IPMI ioctls and typical host-to-BMC access; this is an attacker-driven UAF race, not a layout or victim-state condition.\nPR:L - ipmi_open, ipmi_create_user, and IPMICTL_REGISTER_FOR_CMD perform no capable() check; access is only DAC on /dev/ipmiN, which server and appliance deployments routinely grant to a non-root ipmi/management group for ipmitool/freeipmi, matching established IPMI scoring.\nUI:N - The attacker opens, registers, and closes their own /dev/ipmiN file descriptors and issues ioctls themselves; no victim action such as mounting a filesystem or opening a hostile file is required.\nS:U - This is a host-kernel heap use-after-free of struct cmd_rcvr in the IPMI message handler; impact stays in the same OS security authority with no VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - Without synchronize_rcu(), find_cmd_rcvr() and handle_*_get_msg_cmd() read rcvr-\u003euser from a kmalloc\u0027d cmd_rcvr that _ipmi_destroy_user() already kfree()d; reclaiming that object yields an attacker-controlled pointer and a kernel read primitive, so confidentiality is High per UAF guidance.\nI:H - A sprayed cmd_rcvr supplies a fake ipmi_user pointer; ipmi_alloc_recv_msg() then updates nr_msgs/refcount through that pointer and smi_work later invokes user-\u003ehandler-\u003eipmi_recv_hndl, enabling heap spray and control-flow hijack for arbitrary write and code execution.\nA:H - Use-after-free of cmd_rcvr during the RCU list walk and the subsequent dangling user-pointer dereference readily oopses or panics the kernel under poisoning/KASAN, so availability impact is High per UAF guidance."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:29:55.269Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3088e41292fecf132f85f79af5ee4d620b9ff1b4"
        },
        {
          "url": "https://git.kernel.org/stable/c/5dc0b2a9af95a97861c1bffaf1687a3173e395c5"
        },
        {
          "url": "https://git.kernel.org/stable/c/05ec76cfbce653e07cec19b9b8b20e33449d5d87"
        }
      ],
      "title": "ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89486",
    "datePublished": "2026-09-11T19:43:40.116Z",
    "dateReserved": "2026-09-11T19:38:34.712Z",
    "dateUpdated": "2026-09-13T06:29:55.269Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89486",
      "date": "2026-09-16",
      "epss": "0.00124",
      "percentile": "0.02432"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89486\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-11T20:19:30.297\",\"lastModified\":\"2026-09-13T07:17:11.900\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()\\n\\nCommit 9e91f8a6c868 (\\\"ipmi:msghandler: Remove srcu for the\\nipmi_interfaces list\\\") dropped the synchronize_rcu() between unlinking\\nthe command receivers from intf-\u003ecmd_rcvrs and freeing them, updating\\nonly the comment that explains why the barrier is needed.\\n\\nThe cmd_rcvrs list is still traversed under plain RCU: find_cmd_rcvr()\\nwalks it inside rcu_read_lock(), and handle_ipmb_get_msg_cmd() borrows\\nrcvr-\u003euser from that lookup within the same read-side section. Without\\nthe grace period, _ipmi_destroy_user() can kfree() a cmd_rcvr while a\\nreader still holds a pointer to it, causing a use-after-free.\\n\\nThe rework only made srcu unnecessary for the interfaces list; the\\ncmd_rcvrs list still relies on plain RCU. Restore the synchronize_rcu()\\nbefore freeing the receivers.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/char/ipmi/ipmi_msghandler.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"9e91f8a6c8688e27f4ccce7db457da87d6458836\",\"lessThan\":\"3088e41292fecf132f85f79af5ee4d620b9ff1b4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9e91f8a6c8688e27f4ccce7db457da87d6458836\",\"lessThan\":\"5dc0b2a9af95a97861c1bffaf1687a3173e395c5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9e91f8a6c8688e27f4ccce7db457da87d6458836\",\"lessThan\":\"05ec76cfbce653e07cec19b9b8b20e33449d5d87\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/char/ipmi/ipmi_msghandler.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.16\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.16\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"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:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/05ec76cfbce653e07cec19b9b8b20e33449d5d87\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3088e41292fecf132f85f79af5ee4d620b9ff1b4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5dc0b2a9af95a97861c1bffaf1687a3173e395c5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T06:56:15+00:00",
      "cve": "CVE-2026-89486",
      "id": "CVE-2026-89486",
      "initial_release_date": "2026-09-11T19:43:40.116000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel IPMI: Use-after-free vulnerability leading to system instability or privilege escalation.",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89486.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-16T00:03:04Z",
      "cve": "CVE-2026-89486",
      "id": "CVE-2026-89486",
      "initial_release_date": "2026-09-12T16:27:37Z",
      "product_status:known_not_affected": "353",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89486",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89486.json",
      "version": "5"
    }
  }
}



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.