{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-43203", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-43203" ], "published": "2026-05-06T11:29:17Z", "summary": "atm: fore200e: fix use-after-free in tasklets during device removal", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\natm: fore200e: fix use-after-free in tasklets during device removal\n\nWhen the PCA-200E or SBA-200E adapter is being detached, the fore200e\nis deallocated. However, the tx_tasklet or rx_tasklet may still be running\nor pending, leading to use-after-free bug when the already freed fore200e\nis accessed again in fore200e_tx_tasklet() or fore200e_rx_tasklet().\n\nOne of the race conditions can occur as follows:\n\nCPU 0 (cleanup) | CPU 1 (tasklet)\nfore200e_pca_remove_one() | fore200e_interrupt()\n fore200e_shutdown() | tasklet_schedule()\n kfree(fore200e) | fore200e_tx_tasklet()\n | fore200e-> // UAF\n\nFix this by ensuring tx_tasklet or rx_tasklet is properly canceled before\nthe fore200e is released. Add tasklet_kill() in fore200e_shutdown() to\nsynchronize with any pending or running tasklets. Moreover, since\nfore200e_reset() could prevent further interrupts or data transfers,\nthe tasklet_kill() should be placed after fore200e_reset() to prevent\nthe tasklet from being rescheduled in fore200e_interrupt(). Finally,\nit only needs to do tasklet_kill() when the fore200e state is greater\nthan or equal to FORE200E_STATE_IRQ, since tasklets are uninitialized\nin earlier states. In a word, the tasklet_kill() should be placed in\nthe FORE200E_STATE_IRQ branch within the switch...case structure.\n\nThis bug was identified through static analysis.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.165", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-43203" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/91f25749aaf57c47ae1e12478144e6ea8c8562f2" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/73fbc5d1a9ccb626937500bbd67136f077d8237b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/aba0b4bc09376dfc3d53c826514fe38fc8337f52" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e075ec9b08f862dade8011481058f7eb5f716c57" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/97900f512252a59f23d6ce4ab215cc88fed66e68" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e4ff4e3ffcf9d5aad380cdd1d8cdc008bb34f97d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/5189368f10903956be05062d160b2804bf5e5016" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/8930878101cd40063888a68af73b1b0f8b6c79bc" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T13:16:28Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.5, "cvss_v3_severity": "High", "scenario": "AV:N - ATM link traffic from a remote peer can cause the adapter IRQ path (`fore200e_interrupt()`) to schedule the vulnerable RX/TX tasklets. The freeing side occurs during adapter removal, but the attacker-controlled stimulus reaches the vulnerable tasklet path over the network-facing ATM device.\nAC:H - The bug requires the non-default `CONFIG_ATM_FORE200E_USE_TASKLET` configuration and a removal event overlapping a pending or running tasklet. The remote attacker can keep interrupts likely, but does not fully control the removal side.\nPR:N - A remote ATM peer does not need credentials or local privileges on the vulnerable host to generate traffic that posts adapter interrupts. Local sysfs unbind/module removal would require real root, but the highest-severity reasonable scenario uses unauthenticated remote traffic coinciding with victim-initiated removal.\nUI:R - Network traffic alone does not free `struct fore200e`; a user/admin action or physical hotplug/removal event must detach, unbind, or remove the adapter. Once removal occurs, pending tasklets can access the freed structure.\nS:U - The corruption occurs within the kernel/driver context and affects resources under the same kernel security authority. There is no VM escape, IOMMU bypass, or cross-scope boundary indicated.\nC:H - This is a use-after-free of the driver\u2019s per-device structure, and the tasklets dereference freed pointers and queues after teardown. Per the kernel scoring guidance, UAF memory corruption is treated as enabling high confidentiality impact.\nI:H - The freed `struct fore200e` can be reallocated or corrupted before tasklet execution, creating a plausible control-flow or arbitrary-write primitive. Per the kernel scoring guidance, UAF memory corruption warrants high integrity impact.\nA:H - The tasklets dereference freed driver state after `kfree(fore200e)`, which can directly cause kernel oops, panic, or hang. Any kernel crash from this UAF is high availability impact." } } }