{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89585", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.729Z", "datePublished": "2026-09-11T19:44:50.592Z", "dateUpdated": "2026-10-19T08:49:17.989Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:49:17.989Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nauxdisplay: charlcd: cancel backlight work on registration failure\n\nWith CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before\ncharlcd_register() calls misc_register(). If registration fails, the\ncaller frees the charlcd object while delayed work still contains its\naddress.\n\nAdd charlcd_deinit() to cancel the delayed work and turn the backlight\noff. Use it for both registration rollback and normal unregistration." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - charlcd_register() is reached only from local auxdisplay probe (hd44780 platform, lcd2s I2C, panel parport) on character LCDs in embedded, industrial, and appliance systems; there is no network or USB-host packet path into this misc-registration error path.\nAC:L - CONFIG_CHARLCD_BL_FLASH is the default, so charlcd_init() always queues bl_work (L* poke, 4s) before misc_register(); a second charlcd consumer or LCD_MINOR 156 collision makes registration fail deterministically, then the work runs on the freed object with no attacker-uncontrollable race.\nPR:L - On multi-display or mixed hd44780/lcd2s/panel systems the second probe runs automatically at boot without init-namespace root, and an unprivileged local user can spray the heap in the 4s window; embedded/kiosk sysfs bind is also not strictly root-only. Uncertain vs High, so Low.\nUI:N - The UAF is armed during driver probe and consumed by the kernel workqueue; no victim needs to open /dev/lcd, mount a filesystem, or take any other interactive action.\nS:U - The delayed-work UAF corrupts in-kernel charlcd_priv/work_struct heap state and can escalate only within the host kernel; it does not cross a VM, IOMMU, or sandbox boundary.\nC:H - charlcd_bl_off() does container_of() on the freed delayed_work and reads priv fields, including lcd.ops, from reclaimable slab, giving a use-after-free kernel read primitive.\nI:H - The same callback invokes priv->lcd.ops->backlight on the freed object, so reclaiming the slab with a forged ops table yields a kernel function-pointer call, arbitrary write, and control-flow hijack.\nA:H - Running delayed work after charlcd_free() oopses or panics via mutex_lock on freed bl_tempo_lock or a wild ops pointer, even when the UAF is not fully exploited." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/auxdisplay/charlcd.c" ], "versions": [ { "version": "39f8ea46724efbed3ca021863a22337c31be264c", "lessThan": "cd97b3c68fe3c06c8067cc59d7dff976c5b7ea04", "status": "affected", "versionType": "git" }, { "version": "39f8ea46724efbed3ca021863a22337c31be264c", "lessThan": "22586432c1aba89d9bd33f3173408dac830f220b", "status": "affected", "versionType": "git" }, { "version": "39f8ea46724efbed3ca021863a22337c31be264c", "lessThan": "6eaed64a32e550daf0dc9549742b3ab9e41d984f", "status": "affected", "versionType": "git" }, { "version": "39f8ea46724efbed3ca021863a22337c31be264c", "lessThan": "fe7ba73dde94c5f413b1588cd444b49105015dda", "status": "affected", "versionType": "git" }, { "version": "39f8ea46724efbed3ca021863a22337c31be264c", "lessThan": "84858671842ae5857b9ed1202b62f9045373dcd1", "status": "affected", "versionType": "git" }, { "version": "39f8ea46724efbed3ca021863a22337c31be264c", "lessThan": "ff2fb3c1e60cb247ea3e28c0ea0bea81c18f7755", "status": "affected", "versionType": "git" }, { "version": "39f8ea46724efbed3ca021863a22337c31be264c", "lessThan": "e3e3bf40916c1e810df03958cfa7ba6883cdce79", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/auxdisplay/charlcd.c" ], "versions": [ { "version": "4.12", "status": "affected" }, { "version": "0", "lessThan": "4.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/cd97b3c68fe3c06c8067cc59d7dff976c5b7ea04" }, { "url": "https://git.kernel.org/stable/c/22586432c1aba89d9bd33f3173408dac830f220b" }, { "url": "https://git.kernel.org/stable/c/6eaed64a32e550daf0dc9549742b3ab9e41d984f" }, { "url": "https://git.kernel.org/stable/c/fe7ba73dde94c5f413b1588cd444b49105015dda" }, { "url": "https://git.kernel.org/stable/c/84858671842ae5857b9ed1202b62f9045373dcd1" }, { "url": "https://git.kernel.org/stable/c/ff2fb3c1e60cb247ea3e28c0ea0bea81c18f7755" }, { "url": "https://git.kernel.org/stable/c/e3e3bf40916c1e810df03958cfa7ba6883cdce79" } ], "title": "auxdisplay: charlcd: cancel backlight work on registration failure", "x_generator": { "engine": "bippy-1.2.0" } } } }