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 4B82457F727 for ; Fri, 11 Sep 2026 19:53:17 +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=1789156411; cv=none; b=bN9gpd9lNiikKxHpf/AZrQ9AnZ7W7c3fcaRoor+dP3hJd8FBYVzexca73rbiI5Lpp5HoaN+gN+SMXJk5lKRHxqsPlbTu3IuBHR1b4gn7kTQs9f/OrMyz4dpsGd+I+slHAnCW9UdRSsoMECCDQi1aHeHAllT4gvN0kDDKp3+7Fnc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156411; c=relaxed/simple; bh=oav6Ncld+LFo2geNmlNuyKYmMNCWg46YturhiqT1L1E=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=a2nXkzAQBUdrAfFuGJUItZFFhz4gCo8HFz/xFS8Reilz75cRU/5+/JDQkgrt2Cf4gpu82EFdzI2gxjWTSMo0tPtfqwN8+oq7EZgdVaNTD2cTLEUpR/wo/0mnYhWuKEQ9vGkDxQXiHqTIu4C+hZiW0l/Jvr+SgzDnGIC5TDTxyb4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kpc6VYiI; 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="kpc6VYiI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FCD11F00898; Fri, 11 Sep 2026 19:53:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156396; bh=br3YOr0GHe0s4XAW9eRvhAaqew6ZLUHYSnGKJ6X3ZAs=; h=From:To:Cc:Subject:Date:Reply-To; b=kpc6VYiIsItaYjmgj39zL/T1w9blzg7dWLSIR+lennm8EcsKcs9gmoFXAQyjB7YFz Rmr2zi2K9apcArWMDYWsOfkQlgMoDCcxfqlzkSama3p4YhJNILjZpypU+Gy5ZmX3mU 0xcFHEQVynhIE/GXyvflbzAUoTK/tk2Trzo5CoT0= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89503: ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page() Date: Fri, 11 Sep 2026 21:43:12 +0200 Message-ID: <2026091110-CVE-2026-89503-d44a@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=2484; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=6aVgixDucjLjpa34SoKUnnou4+fsizfjRJ1+5FI3QzY=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIsPunQ65tzFzXoG15u1e1cemCau9/T1Z3bd5Ll4ow tiU41LcEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABOp2MQwP8Lpt9GEAp+v6xcv uC5RNc/XMWW9J8Mc/m+2Z6Jml4iy5Zpyvl2z4tiBAJ4AAA== 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: ring-buffer: Fix subbuf resize race with ring_buffer_alloc_read_page() ring_buffer_alloc_read_page() is racy with ring_buffer_subbuf_order_set, it can allocate a reader page with an outdated order. This isn't a big issue, the user can still re-allocate a new reader page and try again. However, what is more problematic is if the value of subbuf_order changes in the middle of ring_buffer_alloc_read_page(). In that case, bpage->order might not match the actual allocated memory. Use bpage->order for the allocation to prevent this race. The Linux kernel CVE team has assigned CVE-2026-89503 to this issue. Affected and fixed versions =========================== Issue introduced in 6.8 with commit bce761d757452ba5eb77e11fecc37a04b67494e7 and fixed in 6.18.50 with commit 2dc510957fe8fd098ab3c3147ebdf34d00cd2734 Issue introduced in 6.8 with commit bce761d757452ba5eb77e11fecc37a04b67494e7 and fixed in 7.2.4 with commit 53106e9262a310ef2c9a9321168c03705940c678 Issue introduced in 6.8 with commit bce761d757452ba5eb77e11fecc37a04b67494e7 and fixed in 7.3-rc1 with commit e743527c5bfdceda1095bc0a9e596e2aebb6a9c3 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-2026-89503 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: kernel/trace/ring_buffer.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/2dc510957fe8fd098ab3c3147ebdf34d00cd2734 https://git.kernel.org/stable/c/53106e9262a310ef2c9a9321168c03705940c678 https://git.kernel.org/stable/c/e743527c5bfdceda1095bc0a9e596e2aebb6a9c3