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 DB411331203 for ; Sun, 18 Oct 2026 15:31:53 +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=1792337514; cv=none; b=CBGyE1i1jFuSR1pz5bLVEiRMFSj6K2h+yyGGaUIkKsPfjumpEA+PazoNvIKtsKSZPyQtJnnlK1ybC5l8b0X+/3B6Ip0ZnHRWegWDHk/gRJJsW2LWQ7rDr2O9tCjX7yAz27xfFzgIVPBnmkEwLdOZWPp5zOJ+BBUNZK0zvXZV140= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792337514; c=relaxed/simple; bh=XhV0Y1UPGgV1f2R9FQGGmVnYth+Lj+D58VcvrHMtlDE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=A+CQWw4Uvj7BwCvNP18H2vizlqup8m1P0MvRcSzLU6ZkuTpi+qHewnZSwrBv1MvWdKaXaH9W5qbm0hIIP5THjOXjmz8qir0lJ1DKXsrOWOHavEksb4eqBXZ60T1vScpXSjcYiXfOME+f8J/iAMsK13Md/j8jHPODrk8NVYBLEu0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=n3wChMC6; 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="n3wChMC6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EAF0A1F000C4; Sun, 18 Oct 2026 15:31:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792337513; bh=KpvpUiFyv8uN7COtzcGVuQOQrk8TJ37W/54OdKQJv88=; h=From:To:Cc:Subject:Date:Reply-To; b=n3wChMC6KGWe1KhWv6JkSc7/gXs0QEgXjYAt4ZKRlJYIl7AIEzm6fz/PuNm4zaxj/ Sfubj412xS6w0KPNcaO8hxMSBbPZAKKB/RFcm+jaV7N7HRTw0Gc4aWy2nl9KxP0mQj igqkwcD1nwvfc5gMH9hQWaaBdAWzwG2rLcTwOXmg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-98591: bpf: Fix bounds check for skb-backed dynptrs Date: Sun, 18 Oct 2026 17:17:35 +0200 Message-ID: <2026101836-CVE-2026-98591-b5fb@gregkh> X-Mailer: git-send-email 2.56.0 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=3235; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=4BdTJlQmyAtV3YSl56pEX0HlGXDATT2Iea7tjcj6zag=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlXHs04uF+8jPVASvg9vus2Ua5firWNNuw8VVj68LWpJ bfCmW8TOmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiC8QZFnRzcD1srtYxNP7b tGyl4ueT2p0vbjHMzw0Mf/X70PYs+S5m5/dH5wldKLilCgA= 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: bpf: Fix bounds check for skb-backed dynptrs The skb_pointer_if_linear() function checks whether a memory region of length len starting at offset off into the skb is in the linear area, and returns a pointer to the region if so. The check currently subtracts between skb_headlen and offset of the check, and since skb_headlen is unsigned the subtraction can underflow. This causes the bounds check to spuriously pass and generate an arbitrary pointer of the form *(skb->data + off). The only user of this helper is currently skb-backed BPF dynptr code. Returning the wrong pointer leads to the dynptr erroneously being backed with invalid memory. Ensure the subtraction cannot underflow, and fail the check if it would. Use u64 arithmetic to also prevent overflow when calculating (skb_headlen(skb) - off) since off is unsigned. The Linux kernel CVE team has assigned CVE-2026-98591 to this issue. Affected and fixed versions =========================== Issue introduced in 6.6 with commit 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and fixed in 6.6.158 with commit 1b923538598be768e9f2f258a77a083d00e0c78b Issue introduced in 6.6 with commit 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and fixed in 6.12.112 with commit 37877a24758068742fef687a7cf5362360dde1d1 Issue introduced in 6.6 with commit 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and fixed in 6.18.55 with commit 1196903a27cac5c929c7517e987a8d159f20c5e5 Issue introduced in 6.6 with commit 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and fixed in 7.2.9 with commit 39ffceaddb10753eac12785dba6ac0673860b4ac Issue introduced in 6.6 with commit 6f5a630d7c57cd79b1f526a95e757311e32d41e5 and fixed in 7.3-rc5 with commit ed6eec97b534979dcf28b40c389cee57bd6561d4 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-2026-98591 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: include/linux/skbuff.h 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/1b923538598be768e9f2f258a77a083d00e0c78b https://git.kernel.org/stable/c/37877a24758068742fef687a7cf5362360dde1d1 https://git.kernel.org/stable/c/1196903a27cac5c929c7517e987a8d159f20c5e5 https://git.kernel.org/stable/c/39ffceaddb10753eac12785dba6ac0673860b4ac https://git.kernel.org/stable/c/ed6eec97b534979dcf28b40c389cee57bd6561d4