{"id":"CVE-2026-81005","title":"ipmi: si: Fix NULL pointer dereference after failed registration","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nipmi: si: Fix NULL pointer dereference after failed registration\n\ntry_smi_init() allocates new_smi->si_sm and later calls\nipmi_register_smi_mod(), which maps to ipmi_ad…","severity":"medium","cvss":4.1,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-476"],"vendor":"Linux","product":"Linux","affected":["Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 75ecc80ef0614a9f8441ab476fb748d3e919bea8","Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < b11a1e545ad7a2f8f9ba7276b4ae9429c3399456","Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < f390b0e781ca689515b659f94ef05f01497ed833","Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d377bf743f29b41729a084a633874ef9c1a13c6a","Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d4be659a3e56f4eb16039ab8a1162efea086a714","Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 53af3a8bae0a93c1342e1b5519812203332aca8e","Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 8ada17dd4c4ffd6b94621e735d77eda196ce118f","Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 6d920a75df9a83ab096b3cde7a643b656e4fdfeb","Linux 288bd736c8a027040fc261c86a87b65e7bc3f6fa","Linux >= 4.18.10 < 4.19","Linux 4.19"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:46:29.573Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-81005","references":[{"url":"https://git.kernel.org/stable/c/75ecc80ef0614a9f8441ab476fb748d3e919bea8"},{"url":"https://git.kernel.org/stable/c/b11a1e545ad7a2f8f9ba7276b4ae9429c3399456"},{"url":"https://git.kernel.org/stable/c/f390b0e781ca689515b659f94ef05f01497ed833"},{"url":"https://git.kernel.org/stable/c/d377bf743f29b41729a084a633874ef9c1a13c6a"},{"url":"https://git.kernel.org/stable/c/d4be659a3e56f4eb16039ab8a1162efea086a714"},{"url":"https://git.kernel.org/stable/c/53af3a8bae0a93c1342e1b5519812203332aca8e"},{"url":"https://git.kernel.org/stable/c/8ada17dd4c4ffd6b94621e735d77eda196ce118f"},{"url":"https://git.kernel.org/stable/c/6d920a75df9a83ab096b3cde7a643b656e4fdfeb"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81005.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-81005"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532315"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-81005"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81005"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-81005.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00177,"epssPercentile":0.07179,"ingestedAt":"2026-09-14T15:23:07.454Z","slug":"CVE-2026-81005","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nipmi: si: Fix NULL pointer dereference after failed registration\n\ntry_smi_init() allocates new_smi->si_sm and later calls\nipmi_register_smi_mod(), which maps to ipmi_add_smi().\n\nDuring ipmi_add_smi(), the upper IPMI message handler obtains the\ninitial BMC device information through __bmc_get_device_id(). This can\nfail if the BMC does not return a successful response to the Get Device\nID command.\n\nWhen the BMC returns a nonzero completion code, the device-id helper\nretries the command and eventually returns -EIO if the device ID still\ncannot be fetched.\n\nOn this failure path, ipmi_add_smi() logs \"Unable to get the device id\"\nand goes to out_err_started, where it invokes the lower driver's\nshutdown callback. try_smi_init() then logs the returned registration\nfailure:\n\n ipmi_si IPI0001:00: IPMI message handler: Unable to get the device id: -5\n ipmi_si IPI0001:00: Unable to register device: error -5\n\nFor ipmi_si, the shutdown callback is shutdown_smi(), which cleans up\nthe SI state machine data, frees smi_info->si_sm, and sets\nsmi_info->si_sm and smi_info->intf to NULL.\n\nHowever, intf->in_shutdown is not set on this failed-registration\nrollback path. Therefore, the asynchronous redo_bmc_reg work item can\nstill retry BMC device-id probing after the lower driver has already\ncleared its SI state machine data. In the observed case, that retry path\nreached start_next_msg(), which passed the NULL smi_info->si_sm pointer\nto the selected KCS state machine handler:\n\nBUG: unable to handle kernel NULL pointer dereference at 0000000000000000\nWorkqueue: events redo_bmc_reg [ipmi_msghandler]\nRIP: start_kcs_transaction+0x2c/0x190 [ipmi_si]\nCall Trace:\n start_next_msg+0x50/0x80 [ipmi_si]\n check_start_timer_thread.part.9+0x3b/0x50 [ipmi_si]\n sender+0x69/0x80 [ipmi_si]\n i_ipmi_request+0x2ac/0x9d0 [ipmi_msghandler]\n __get_device_id.isra.29+0xaa/0x180 [ipmi_msghandler]\n __bmc_get_device_id+0xef/0x950 [ipmi_msghandler]\n redo_bmc_reg+0x52/0x60 [ipmi_msghandler]\n process_one_work+0x1a7/0x360\n\nSet intf->in_shutdown on the out_err_started path before invoking the\nlower driver's shutdown callback. This prevents later redo_bmc_reg\nretries from using an interface whose lower driver state has been\ncleaned up, and applies the same shutdown state to other IPMI interfaces\nas well.\n\n## Affected\n\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 75ecc80ef0614a9f8441ab476fb748d3e919bea8`\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < b11a1e545ad7a2f8f9ba7276b4ae9429c3399456`\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < f390b0e781ca689515b659f94ef05f01497ed833`\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d377bf743f29b41729a084a633874ef9c1a13c6a`\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < d4be659a3e56f4eb16039ab8a1162efea086a714`\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 53af3a8bae0a93c1342e1b5519812203332aca8e`\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 8ada17dd4c4ffd6b94621e735d77eda196ce118f`\n- `Linux >= 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 < 6d920a75df9a83ab096b3cde7a643b656e4fdfeb`\n- `Linux 288bd736c8a027040fc261c86a87b65e7bc3f6fa`\n- `Linux >= 4.18.10 < 4.19`\n- `Linux 4.19`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81005.json)","depth":"sunlit","depthScore":23,"depthScoreParts":{"impact":22.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":204140,"id":"CVE-2026-81005","ts":1789490232088,"field":"cvss","old":null,"new":"4.1"},{"seq":204139,"id":"CVE-2026-81005","ts":1789490232088,"field":"severity","old":"none","new":"medium"}]}