From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67F4B560ADF for ; Fri, 11 Sep 2026 19:47:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156067; cv=none; b=R5T2tCXw+jb+lIVGBaj0M1rDplfsJk7H2q4rBiSAvYWbz3tvIruUipEhuZzMAUvorB1yvGrvCjoiFtnjFI4+2uKMliKzTypqSDYUJBiK8AHWQydTsi7OTTQLbgkSqv2uctylkfBGZi91dghm7MuMKtMNAKoshA8a/t9q8kFFpnU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156067; c=relaxed/simple; bh=du5xWBNmIzmKZpIaztfxYdtVf0Dp2a3ZT9+wcfgkGnc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=s79UzC688NWGmSOcNWJRergv96B092YnOypzetC+JeYsxv//AXzS5qs59bbSkFY6JX2XNpqmoSxFe+1vZFffl63d0JUamujYXWLehTAtiYVL5oRTxFLmZ8xhpO+ntAU2f1st3h4dlapLjWee9R7WIO75C4jDE8TZ8yux2DNEp14= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mEZwNKS5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mEZwNKS5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C84E91F0089A; Fri, 11 Sep 2026 19:47:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156055; bh=6gLdeLjORmysPS2IPWUl2EWJWxSTLOaLUXQf2GzCcv0=; h=From:To:Cc:Subject:Date:Reply-To; b=mEZwNKS5vbVu087nW6aUW5DLQGn3/tQlGDFmL0UX3VVTSqWs2WC6hsXMCBg630m9Z p65AD3cDfX/BzPBiVfy9V9k0njIS8UO6FpNjdi4pJMuJ08Bs0H9062NMFzWBn+b9e+ mq2+KTQaYLgmAvFnhmxyOx3gE8XdGbJ4u4fcfY1Q= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80973: ALSA: 6fire: bound the MIDI event length from the device Date: Fri, 11 Sep 2026 21:41:19 +0200 Message-ID: <2026091144-CVE-2026-80973-9155@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4388; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=lScXXtBr+BWCDidHZNjVq+pQCbQL5dcJP8hntT0JDOQ=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIm2ecim9rOPekFusv/m6R7x9i86ThhXCjX6BHWE5m 09uCvrZEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABOZn8gwzyLlSrKY1OFdZWHT ONS/rzGr0z6zgmGe0tMZv2r/VrjeOqaj0/61a8eliYV9AA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: ALSA: 6fire: bound the MIDI event length from the device usb6fire_comm_receiver_handler() forwards a MIDI event using a length byte the device supplies, with no bound and no check that the transfer delivered that many bytes: if (!urb->status) { if (rt->receiver_buffer[0] == 0x10) /* midi in event */ if (midi_rt) midi_rt->in_received(midi_rt, rt->receiver_buffer + 2, rt->receiver_buffer[1]); } receiver_buffer is a 64-byte kzalloc() buffer (COMM_RECEIVER_BUFSIZE), so only 62 bytes follow the two-byte header. receiver_buffer[1] is a u8 the device chooses, so a device that answers with 0x10 and a length of 0xFF makes snd_rawmidi_receive() read 255 bytes starting two bytes into a 64-byte object. The bytes past the buffer are handed to userspace through the rawmidi read path. urb->actual_length is not consulted either, so a short transfer leaves both the type byte and the length byte at their previous values and the handler acts on stale data. The receiver URB is submitted from usb6fire_comm_init() at probe, so the read happens on plug with no user action; forwarding to userspace also needs a MIDI input substream open, since usb6fire_midi_in_received() only calls snd_rawmidi_receive() when rt->in is set. KASAN on 7.2.0-rc5 (arm64), single packet from an emulated device: BUG: KASAN: slab-out-of-bounds in snd_rawmidi_receive Read of size 255 at addr ffff000009f64682 by task bash/183 __asan_memcpy snd_rawmidi_receive usb6fire_midi_in_received [snd_usb_6fire] usb6fire_comm_receiver_handler [snd_usb_6fire] Allocated by task 11: usb6fire_comm_init [snd_usb_6fire] usb6fire_chip_probe [snd_usb_6fire] The buggy address is located 2 bytes inside of allocated 64-byte region [ffff000009f64680, ffff000009f646c0) Reject the event when the length exceeds the bytes that follow the header, and require the transfer to have delivered the header plus that many bytes. The receiver URB is submitted with a 64-byte transfer_buffer_length, so a genuine device cannot deliver an event longer than those 62 bytes and nothing valid is dropped. Discovered by XBOW, triaged by Baul Lee The Linux kernel CVE team has assigned CVE-2026-80973 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.39 with commit c6d43ba816d1cf1d125bfbfc938f2a28a87facf9 and fixed in 6.12.109 with commit 466e911bbbbb779bb06337e35a286e5ca7af16b3 Issue introduced in 2.6.39 with commit c6d43ba816d1cf1d125bfbfc938f2a28a87facf9 and fixed in 6.18.50 with commit 2a6f6fba3bd31d2e8c957fefa29156e35e5e75d5 Issue introduced in 2.6.39 with commit c6d43ba816d1cf1d125bfbfc938f2a28a87facf9 and fixed in 7.2.4 with commit 34816e2cfeabafb8eccf54687186ce25699e8363 Issue introduced in 2.6.39 with commit c6d43ba816d1cf1d125bfbfc938f2a28a87facf9 and fixed in 7.3-rc1 with commit a478893b59e36cfe7d77a76b352f2db55502e879 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-80973 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: sound/usb/6fire/comm.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/466e911bbbbb779bb06337e35a286e5ca7af16b3 https://git.kernel.org/stable/c/2a6f6fba3bd31d2e8c957fefa29156e35e5e75d5 https://git.kernel.org/stable/c/34816e2cfeabafb8eccf54687186ce25699e8363 https://git.kernel.org/stable/c/a478893b59e36cfe7d77a76b352f2db55502e879