Vulnerability-Lookup

GHSA-VQPC-PM2X-2835

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

In the Linux kernel, the following vulnerability has been resolved:

ipmi: Fix user refcount underflow in event delivery

ipmi_alloc_recv_msg(user) takes the temporary user reference owned by the receive message, and ipmi_free_recv_msg() drops it again. If event delivery fails after allocating receive messages for earlier users, handle_read_event_rsp() rolls those messages back with ipmi_free_recv_msg().

That rollback path still drops user->refcount explicitly after freeing each message. The extra put can free a user that remains linked on intf->users, so later event delivery may dereference a freed user or trip refcount_t's addition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire another reference.

Remove the stale explicit put and the now-dead user assignment. Keep the list_del() and ipmi_free_recv_msg() calls; they are the required rollback operations.

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-2026-72042"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:13Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: Fix user refcount underflow in event delivery\n\nipmi_alloc_recv_msg(user) takes the temporary user reference owned by the\nreceive message, and ipmi_free_recv_msg() drops it again. If event delivery\nfails after allocating receive messages for earlier users,\nhandle_read_event_rsp() rolls those messages back with\nipmi_free_recv_msg().\n\nThat rollback path still drops user-\u003erefcount explicitly after freeing each\nmessage. The extra put can free a user that remains linked on intf-\u003eusers,\nso later event delivery may dereference a freed user or trip refcount_t\u0027s\naddition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire\nanother reference.\n\nRemove the stale explicit put and the now-dead user assignment. Keep the\nlist_del() and ipmi_free_recv_msg() calls; they are the required rollback\noperations.",
  "id": "GHSA-vqpc-pm2x-2835",
  "modified": "2026-08-17T06:33:06Z",
  "published": "2026-08-15T06:32:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72042"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6aa9e61c46465d231e9beddf56af7effd71be682"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7be349d4fcc5e065295b83418a22d27a68afbdb6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ddbb6e3dc9bb4743de686aa1598c31e745cee76b"
    }
  ],
  "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-2026-72042 (GCVE-0-2026-72042)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:52 – Updated: 2026-08-17 05:39

Title

ipmi: Fix user refcount underflow in event delivery

Summary

In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix user refcount underflow in event delivery ipmi_alloc_recv_msg(user) takes the temporary user reference owned by the receive message, and ipmi_free_recv_msg() drops it again. If event delivery fails after allocating receive messages for earlier users, handle_read_event_rsp() rolls those messages back with ipmi_free_recv_msg(). That rollback path still drops user->refcount explicitly after freeing each message. The extra put can free a user that remains linked on intf->users, so later event delivery may dereference a freed user or trip refcount_t's addition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire another reference. Remove the stale explicit put and the now-dead user assignment. Keep the list_del() and ipmi_free_recv_msg() calls; they are the required rollback operations.

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 mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/ddbb6e3dc9bb4743d…
https://git.kernel.org/stable/c/7be349d4fcc5e0652…
https://git.kernel.org/stable/c/6aa9e61c46465d231…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: b52da4054ee0bf9ecb44996f2c83236ff50b3812 , < ddbb6e3dc9bb4743de686aa1598c31e745cee76b (git) Affected: b52da4054ee0bf9ecb44996f2c83236ff50b3812 , < 7be349d4fcc5e065295b83418a22d27a68afbdb6 (git) Affected: b52da4054ee0bf9ecb44996f2c83236ff50b3812 , < 6aa9e61c46465d231e9beddf56af7effd71be682 (git) Affected: f63723ca7d7623f9dae1990973cd158671f03c56 (git) Affected: 348121b29594d42d1635648fd3ed31dfa25351d5 (git) Affected: 53d6e403affbf6df2c859a0ea00ccfc1e72090ca (git) Affected: 0ed73be9a2547ffb9b5c1d879ad9bfab73d920b5 (git) Affected: 6.1.157 , < 6.2 (semver) Affected: 6.6.113 , < 6.7 (semver) Affected: 6.12.54 , < 6.13 (semver) Affected: 6.17.4 , < 6.18 (semver)
Linux	Linux	Affected: 6.18 Unaffected: 0 , < 6.18 (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/char/ipmi/ipmi_msghandler.c"
          ],
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          "vendor": "Linux",
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            {
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              "status": "affected",
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              "versionType": "git"
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            {
              "lessThan": "7be349d4fcc5e065295b83418a22d27a68afbdb6",
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              "version": "b52da4054ee0bf9ecb44996f2c83236ff50b3812",
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              "status": "affected",
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              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "53d6e403affbf6df2c859a0ea00ccfc1e72090ca",
              "versionType": "git"
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            {
              "status": "affected",
              "version": "0ed73be9a2547ffb9b5c1d879ad9bfab73d920b5",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "semver"
            },
            {
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
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              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
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              "versionType": "semver"
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              "version": "7.2",
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        }
      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: Fix user refcount underflow in event delivery\n\nipmi_alloc_recv_msg(user) takes the temporary user reference owned by the\nreceive message, and ipmi_free_recv_msg() drops it again. If event delivery\nfails after allocating receive messages for earlier users,\nhandle_read_event_rsp() rolls those messages back with\nipmi_free_recv_msg().\n\nThat rollback path still drops user-\u003erefcount explicitly after freeing each\nmessage. The extra put can free a user that remains linked on intf-\u003eusers,\nso later event delivery may dereference a freed user or trip refcount_t\u0027s\naddition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire\nanother reference.\n\nRemove the stale explicit put and the now-dead user assignment. Keep the\nlist_del() and ipmi_free_recv_msg() calls; they are the required rollback\noperations."
        }
      ],
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            "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 - Exploitation requires local setup via /dev/ipmiN (open, IPMICTL_SET_GETS_EVENTS, message flooding); the refcount bug is in handle_read_event_rsp() during host-side BMC event processing, not via a remote packet path to the kernel.\nAC:L - An attacker with IPMI device access controls both sides: multiple fds, gets_events registration, filling one user\u0027s outstanding-message limit to force EBUSY, and generating/waiting for BMC events via their own IPMI commands.\nPR:L - ipmi_open/ipmi_create_user perform no capability() check; access is gated only by /dev/ipmiN DAC, and BMC-equipped servers often grant that node to a non-root management group (ipmi) for ipmitool/freeipmi.\nUI:N - No victim interaction is required; the attacker drives all setup and triggering through their own IPMI file descriptors and ioctls.\nS:U - This is a host-kernel heap use-after-free of struct ipmi_user within the same OS security authority, with no VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - Premature free_ipmi_user() leaves a dangling ipmi_user on intf-\u003eusers; later iterations call kref_get and read handler pointers from freed slab memory, yielding arbitrary kernel read primitives per UAF guidance.\nI:H - Freed ipmi_user objects contain function pointers (handler-\u003eipmi_recv_hndl); smi_work later invokes these on reclaimed memory, enabling heap spray and control-flow hijack for arbitrary kernel write/code execution.\nA:H - The extra kref_put causes refcount underflow warnings and use-after-free of ipmi_user; subsequent event delivery dereferences freed memory and readily triggers kernel oops/panic under KASAN/poisoning."
            }
          ]
        }
      ],
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        "dateUpdated": "2026-08-17T05:39:41.572Z",
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        {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72042",
    "datePublished": "2026-08-15T05:52:01.454Z",
    "dateReserved": "2026-08-09T03:40:39.902Z",
    "dateUpdated": "2026-08-17T05:39:41.572Z",
    "state": "PUBLISHED"
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}

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.

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.

Action not permitted

GHSA-VQPC-PM2X-2835

CVE-2026-72042 (GCVE-0-2026-72042)

Tags

Sightings

Nomenclature