CVE-2025-40202 (GCVE-0-2025-40202)

Vulnerability from cvelistv5 – Published: 2025-11-12 21:56 – Updated: 2026-08-05 12:08
VLAI
Title
ipmi: Rework user message limit handling
Summary
In the Linux kernel, the following vulnerability has been resolved: ipmi: Rework user message limit handling The limit on the number of user messages had a number of issues, improper counting in some cases and a use after free. Restructure how this is all done to handle more in the receive message allocation routine, so all refcouting and user message limit counts are done in that routine. It's a lot cleaner and safer.
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
Linux Linux Affected: 8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82 , < f63723ca7d7623f9dae1990973cd158671f03c56 (git)
Affected: 8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82 , < 348121b29594d42d1635648fd3ed31dfa25351d5 (git)
Affected: 8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82 , < 53d6e403affbf6df2c859a0ea00ccfc1e72090ca (git)
Affected: 8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82 , < 0ed73be9a2547ffb9b5c1d879ad9bfab73d920b5 (git)
Affected: 8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82 , < b52da4054ee0bf9ecb44996f2c83236ff50b3812 (git)
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Linux Linux Affected: 5.19
Unaffected: 0 , < 5.19 (semver)
Unaffected: 6.1.157 , ≤ 6.1.* (semver)
Unaffected: 6.6.113 , ≤ 6.6.* (semver)
Unaffected: 6.12.54 , ≤ 6.12.* (semver)
Unaffected: 6.17.4 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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{
  "containers": {
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      "affected": [
        {
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          "product": "Linux",
          "programFiles": [
            "drivers/char/ipmi/ipmi_msghandler.c"
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          "vendor": "Linux",
          "versions": [
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              "version": "5.19"
            },
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              "status": "unaffected",
              "version": "0",
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              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.6.113",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.54",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "versionEndExcluding": "6.1.157",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
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                {
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: Rework user message limit handling\n\nThe limit on the number of user messages had a number of issues,\nimproper counting in some cases and a use after free.\n\nRestructure how this is all done to handle more in the receive message\nallocation routine, so all refcouting and user message limit counts\nare done in that routine.  It\u0027s a lot cleaner and safer."
        }
      ],
      "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 vulnerable paths are entered through ioctls on the `/dev/ipmiN` character device (`IPMICTL_SEND_MSG`, `IPMICTL_SET_GETS_EVENTS_CMD`, `IPMICTL_REGISTER_FOR_CMD`), i.e. local access to the machine. Although BMC-originated IPMB/LAN traffic also exercises the same miscounted paths, the reliable and documented trigger is the local device interface.\nAC:L - The counting imbalance is deterministic, not a race: `ipmi_set_gets_events()` sets `msg-\u003euser` without incrementing `nr_msgs` while delivery always decrements it, so a single `IPMICTL_SET_GETS_EVENTS_CMD` that drains queued events reliably underflows the counter and defeats the allocation limit. No memory-layout or timing conditions outside the attacker\u0027s control are required.\nPR:L - Neither `ipmi_devintf.c` nor `ipmi_msghandler.c` performs any capability check \u2014 reaching the bug only requires an open file descriptor on `/dev/ipmiN`, which server, appliance and embedded/telecom deployments commonly grant to an unprivileged monitoring/management group via udev so agents such as ipmitool can run without root.\nUI:N - The attacker performs everything itself with open()/ioctl() on the IPMI device; no victim action, mount, or file-open by another user is needed.\nS:U - The corrupted state (`struct ipmi_recv_msg`, `struct ipmi_user`, the driver\u0027s static watchdog/poweroff message objects) and all consequences stay within the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The fix removes a genuine use-after-free (`ipmi_free_recv_msg(msg)` followed by dereferencing `msg-\u003euser`) plus release of caller-owned message objects; a freed `ipmi_recv_msg`/`ipmi_user` that the attacker can reclaim via heap grooming yields a controlled read primitive, and IPMI messages carry BMC/management-plane data.\nI:H - The use-after-free performs an atomic decrement through a stale `msg-\u003euser` pointer \u2014 an attacker-placed replacement object turns that into an arbitrary 32-bit decrement primitive, and the double release of the watchdog/poweroff static messages corrupts driver state, both leveragable toward control-flow hijack.\nA:H - Underflowing `nr_msgs` makes the signed/unsigned comparison reject every further request with `-EBUSY`, permanently disabling IPMI management (the reported real-world failure), while simultaneously defeating the `max_msgs_per_user` guard that exists specifically to stop a rogue program exhausting kernel memory; the use-after-free additionally causes oopses."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:08:30.982Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f63723ca7d7623f9dae1990973cd158671f03c56"
        },
        {
          "url": "https://git.kernel.org/stable/c/348121b29594d42d1635648fd3ed31dfa25351d5"
        },
        {
          "url": "https://git.kernel.org/stable/c/53d6e403affbf6df2c859a0ea00ccfc1e72090ca"
        },
        {
          "url": "https://git.kernel.org/stable/c/0ed73be9a2547ffb9b5c1d879ad9bfab73d920b5"
        },
        {
          "url": "https://git.kernel.org/stable/c/b52da4054ee0bf9ecb44996f2c83236ff50b3812"
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      ],
      "title": "ipmi: Rework user message limit handling",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40202",
    "datePublished": "2025-11-12T21:56:34.527Z",
    "dateReserved": "2025-04-16T07:20:57.179Z",
    "dateUpdated": "2026-08-05T12:08:30.982Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-40202",
      "date": "2026-08-07",
      "epss": "0.00136",
      "percentile": "0.03502"
    },
    "microsoft_vex": {
      "current_release_date": "2025-12-07T01:35:54.000Z",
      "cve": "CVE-2025-40202",
      "id": "msrc_CVE-2025-40202",
      "initial_release_date": "2025-11-02T00:00:00.000Z",
      "product_status:fixed": "1",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "ipmi: Rework user message limit handling",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-40202.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-40202\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-11-12T22:15:47.403\",\"lastModified\":\"2026-07-30T06:24:17.343\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nipmi: Rework user message limit handling\\n\\nThe limit on the number of user messages had a number of issues,\\nimproper counting in some cases and a use after free.\\n\\nRestructure how this is all done to handle more in the receive message\\nallocation routine, so all refcouting and user message limit counts\\nare done in that routine.  It\u0027s a lot cleaner and safer.\"}],\"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\":\"8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82\",\"lessThan\":\"f63723ca7d7623f9dae1990973cd158671f03c56\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82\",\"lessThan\":\"348121b29594d42d1635648fd3ed31dfa25351d5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82\",\"lessThan\":\"53d6e403affbf6df2c859a0ea00ccfc1e72090ca\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82\",\"lessThan\":\"0ed73be9a2547ffb9b5c1d879ad9bfab73d920b5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8e76741c3d8b20dfa2d6c30fa10ff927cfd93d82\",\"lessThan\":\"b52da4054ee0bf9ecb44996f2c83236ff50b3812\",\"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\":\"5.19\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.19\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.157\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.113\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.54\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.17.4\",\"lessThanOrEqual\":\"6.17.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18\",\"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/0ed73be9a2547ffb9b5c1d879ad9bfab73d920b5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/348121b29594d42d1635648fd3ed31dfa25351d5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/53d6e403affbf6df2c859a0ea00ccfc1e72090ca\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b52da4054ee0bf9ecb44996f2c83236ff50b3812\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f63723ca7d7623f9dae1990973cd158671f03c56\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-30T10:16:55+00:00",
      "cve": "CVE-2025-40202",
      "id": "CVE-2025-40202",
      "initial_release_date": "2025-11-12T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ipmi: Rework user message limit handling",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-40202.json",
      "version": "3"
    }
  }
}



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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

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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.