Vulnerability-Lookup

GHSA-6JQ9-CVJW-V2H5

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-13 09:32

Details

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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89486"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:30Z",
    "severity": "HIGH"
  },
  "details": "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.",
  "id": "GHSA-6jq9-cvjw-v2h5",
  "modified": "2026-09-13T09:32:13Z",
  "published": "2026-09-11T21:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89486"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/05ec76cfbce653e07cec19b9b8b20e33449d5d87"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3088e41292fecf132f85f79af5ee4d620b9ff1b4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5dc0b2a9af95a97861c1bffaf1687a3173e395c5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-10-19 08:47

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

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6639 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/3088e41292fecf132…
https://git.kernel.org/stable/c/5dc0b2a9af95a9786…
https://git.kernel.org/stable/c/05ec76cfbce653e07…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9e91f8a6c8688e27f4ccce7db457da87d6458836 , < 3088e41292fecf132f85f79af5ee4d620b9ff1b4 (git) Affected: 9e91f8a6c8688e27f4ccce7db457da87d6458836 , < 5dc0b2a9af95a97861c1bffaf1687a3173e395c5 (git) Affected: 9e91f8a6c8688e27f4ccce7db457da87d6458836 , < 05ec76cfbce653e07cec19b9b8b20e33449d5d87 (git)
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 , ≤ * (original_commit_for_fix)

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{
  "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",
              "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",
                  "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": "2026-10-19T08:47:36.844Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "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": "2026-10-19T08:47:36.844Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.

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