{"api_version":"1","generated_at":"2026-08-17T23:06:18+00:00","cve":"CVE-2026-72042","urls":{"html":"https://cve.report/CVE-2026-72042","api":"https://cve.report/api/cve/CVE-2026-72042.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72042","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72042"},"summary":{"title":"ipmi: Fix user refcount underflow in event delivery","description":"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->refcount explicitly after freeing each\nmessage. The extra put can free a user that remains linked on intf->users,\nso later event delivery may dereference a freed user or trip refcount_t's\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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:21:13","updated_at":"2026-08-17 06:18:02"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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"}}],"references":[{"url":"https://git.kernel.org/stable/c/7be349d4fcc5e065295b83418a22d27a68afbdb6","name":"https://git.kernel.org/stable/c/7be349d4fcc5e065295b83418a22d27a68afbdb6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6aa9e61c46465d231e9beddf56af7effd71be682","name":"https://git.kernel.org/stable/c/6aa9e61c46465d231e9beddf56af7effd71be682","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ddbb6e3dc9bb4743de686aa1598c31e745cee76b","name":"https://git.kernel.org/stable/c/ddbb6e3dc9bb4743de686aa1598c31e745cee76b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72042","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72042","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b52da4054ee0bf9ecb44996f2c83236ff50b3812 ddbb6e3dc9bb4743de686aa1598c31e745cee76b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b52da4054ee0bf9ecb44996f2c83236ff50b3812 7be349d4fcc5e065295b83418a22d27a68afbdb6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b52da4054ee0bf9ecb44996f2c83236ff50b3812 6aa9e61c46465d231e9beddf56af7effd71be682 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f63723ca7d7623f9dae1990973cd158671f03c56 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 348121b29594d42d1635648fd3ed31dfa25351d5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 53d6e403affbf6df2c859a0ea00ccfc1e72090ca git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0ed73be9a2547ffb9b5c1d879ad9bfab73d920b5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.1.157 6.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.113 6.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.54 6.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.17.4 6.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"72042","cve":"CVE-2026-72042","epss":"0.001980000","percentile":"0.099120000","score_date":"2026-08-16","updated_at":"2026-08-17 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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->refcount explicitly after freeing each\nmessage. The extra put can free a user that remains linked on intf->users,\nso later event delivery may dereference a freed user or trip refcount_t's\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."}],"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 - 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's 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->users; 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->ipmi_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."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:39:41.572Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/ddbb6e3dc9bb4743de686aa1598c31e745cee76b"},{"url":"https://git.kernel.org/stable/c/7be349d4fcc5e065295b83418a22d27a68afbdb6"},{"url":"https://git.kernel.org/stable/c/6aa9e61c46465d231e9beddf56af7effd71be682"}],"title":"ipmi: Fix user refcount underflow in event delivery","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","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"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:21:13","lastModifiedDate":"2026-08-17 06:18:02","problem_types":[],"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}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72042","Ordinal":"1","Title":"ipmi: Fix user refcount underflow in event delivery","CVE":"CVE-2026-72042","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72042","Ordinal":"1","NoteData":"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->refcount explicitly after freeing each\nmessage. The extra put can free a user that remains linked on intf->users,\nso later event delivery may dereference a freed user or trip refcount_t's\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.","Type":"Description","Title":"ipmi: Fix user refcount underflow in event delivery"}]}}}