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 8BF783A873A for ; Sun, 19 Jul 2026 15:44:52 +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=1784475893; cv=none; b=h8kI7jJlJHFTMn8ftioxhcqWEMogLmkehzFu9VS23qBVtHGaMOp+Olpwe5byG83QkBZJLiw0YGOysQDpE3t3M+bw1S7ofxmg5lP/Jz0YhRQU5A825vTNyCC0cmGgrdT7+vVy3JsY8pXyWjA0TzdnckCxsIPaBqxrzBKOxWvJQAM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784475893; c=relaxed/simple; bh=b5z5+nyXjFWxgwlDotfXGSfRiDZxGewND8qUjdqsJSM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=SXPR6sEuNwDAf/0j937qApsdRwFAYeZbDEh6RYGHMq1gJkOLqX9Jr4ElEiPRIwjCYgQaiwrFC2rHCU4TOriw4rRHz3jW5mY/Qxjoa5dULhVVs6epOQ8FO0Gu2XPdTdiJxw6//Z80gv1VCEjSHO3ShMjtfA7DgVaSmVnuCianibw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qg8UEAoR; 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="qg8UEAoR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F06A21F000E9; Sun, 19 Jul 2026 15:44:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784475892; bh=Vqnlt7Rj6pQAHD4gwoTRT4fzo9np86PRFDEoAkikk/0=; h=From:To:Cc:Subject:Date:Reply-To; b=qg8UEAoRs8dMrxArpmFh8/0E3HnVC5RAgUH1B50XJmCl6vYXH7+4KhLM6KP3U1ysS N+Z2HkWLZSlunuutuAUgP7oaUu/BkiVqIaZjPmqbHZEgv0jXZrxl3lT9tt2cptMID3 5FgiEwepSXa9knHklFmNs9Z9gsC0N6obfUIh9l70= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-64121: net: ifb: report ethtool stats over num_tx_queues Date: Sun, 19 Jul 2026 17:39:43 +0200 Message-ID: <2026071924-CVE-2026-64121-7da8@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=4252; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=O0Y5e+hyHMTaEEHx9+t8I32ysW5y05JJZ+4Mg5rShKc=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkx7wtUdzAtTktgYWNZWnz8GVcFn+qjP7J5tjNPfL/t/ 5dj0vH5HbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCRic4MMxk37FC9tLzrldm0 3kcMORt42wxmazLM91bOfL1QsK759+bSq9bf+484O7f9BwA= 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: net: ifb: report ethtool stats over num_tx_queues ifb_dev_init() allocates dp->tx_private to dev->num_tx_queues entries via kzalloc_objs(*txp, dev->num_tx_queues). Both IFB per-queue RX and TX stats live in those entries: ifb_xmit() updates txp->rx_stats using the skb queue mapping, ifb_ri_tasklet() updates txp->tx_stats, and ifb_stats64() aggregates both over dev->num_tx_queues. The ethtool stats callbacks instead size and walk the per-queue stats with dev->real_num_rx_queues and dev->real_num_tx_queues. With an asymmetric device where the RX queue count exceeds the TX queue count, for example: ip link add name ifb10 numtxqueues 1 numrxqueues 8 type ifb ethtool -S ifb10 ifb_get_ethtool_stats() indexes past the tx_private allocation and copies adjacent slab data through ETHTOOL_GSTATS. Use dev->num_tx_queues consistently for the stats strings, the stats count, and the stats data walks. This reports one RX stats group and one TX stats group for each backing ifb_q_private entry, which is the queue set IFB can actually populate. Reproduced under UML+KASAN at v7.1-rc2: BUG: KASAN: slab-out-of-bounds in ifb_fill_stats_data+0x3c/0xae Read of size 8 at addr 0000000062dbd228 by task ethtool/36 ifb_fill_stats_data+0x3c/0xae ifb_get_ethtool_stats+0xc0/0x129 __dev_ethtool+0x1ca5/0x363c dev_ethtool+0x123/0x1b3 dev_ioctl+0x56c/0x744 sock_do_ioctl+0x15f/0x1b2 sock_ioctl+0x4d5/0x50a sys_ioctl+0xd8b/0xde9 With the patch applied, the same UML+KASAN repro is silent and ethtool -S ifb10 reports only the stats backed by the single allocated tx_private entry. The Linux kernel CVE team has assigned CVE-2026-64121 to this issue. Affected and fixed versions =========================== Issue introduced in 5.17 with commit a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 and fixed in 6.1.175 with commit 6afdb8113cb007f9332f59a9b7fd45731b8a9de5 Issue introduced in 5.17 with commit a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 and fixed in 6.6.142 with commit 16bd798cb6d8337d7c3eea1adc412f31b5181d5b Issue introduced in 5.17 with commit a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 and fixed in 6.12.92 with commit 301a554e458e2f5ec47f2c336a7cb03b877f9fd6 Issue introduced in 5.17 with commit a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 and fixed in 6.18.34 with commit f8a5a76b4a683043c6eff2a060bcaa17f9316ad5 Issue introduced in 5.17 with commit a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 and fixed in 7.0.11 with commit 2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4 Issue introduced in 5.17 with commit a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 and fixed in 7.1 with commit 5db89c99566fc4728cc92e941d8e1975711e24b5 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-2026-64121 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: drivers/net/ifb.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/6afdb8113cb007f9332f59a9b7fd45731b8a9de5 https://git.kernel.org/stable/c/16bd798cb6d8337d7c3eea1adc412f31b5181d5b https://git.kernel.org/stable/c/301a554e458e2f5ec47f2c336a7cb03b877f9fd6 https://git.kernel.org/stable/c/f8a5a76b4a683043c6eff2a060bcaa17f9316ad5 https://git.kernel.org/stable/c/2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4 https://git.kernel.org/stable/c/5db89c99566fc4728cc92e941d8e1975711e24b5