From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E79613A5434 for ; Fri, 8 May 2026 14:22:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250152; cv=none; b=mzxSjMccliQDftT5TeGvFFIQMW4Rugmrf4xJKXh6R4cwV2vR94lCGx/YqKmBcDZZCmhWCmWxWyP/bN3bSTS4c59ZlYtPOv+Y0O9PsxDkfMvEuAqTRjswKhUcuRX+9/pWY0yNPE37QRSDPlyV86hTsp/UIRiwLnBZfPkCLhQCI/c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250152; c=relaxed/simple; bh=WaA4Q61KHBRWv+py5/uaHhvofB4GLm3uh1f8ITSa93Q=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=kZdDfjiOMAG2Mw5F+Mt5mQ6Mn56bz9BEKzWOKgqlxPPFb7UQhphSE+fnFJpYcb1j5d4S277fPFoJEZ0z9zPVhYAdHhVfsci1plJ9TRC1NJfWs7ByEf+C4vO8SPaws21eR0NdkCW3d9/KX6gAP+59UpUXe/WIMGfslSLCDlj3YUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xuwkG3bn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xuwkG3bn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52F73C2BCB0; Fri, 8 May 2026 14:22:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778250151; bh=WaA4Q61KHBRWv+py5/uaHhvofB4GLm3uh1f8ITSa93Q=; h=From:To:Cc:Subject:Date:Reply-To:From; b=xuwkG3bnALVgCD7VSIGJs7ej/AU36g+7uoZFoUJBxsw8YphKFBOb9bgO1ANuA4cB7 hEAdCI/QYzRICYNfUuRyhEHafiA1nhVkj7JB89ZZkcXjkqIwJKRGqFjKbmr+/kF5MA NOXzBiPt+Z191IgUDPAi4WC9GRu2bXtaEqLeIoSc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-43364: ublk: fix NULL pointer dereference in ublk_ctrl_set_size() Date: Fri, 8 May 2026 16:21:33 +0200 Message-ID: <2026050827-CVE-2026-43364-7be5@gregkh> X-Mailer: git-send-email 2.54.0 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=2651; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=s+m/v6S7uOrIXo0jyyI6cyaOY+pnTDBJ+HUqNp1hqOo=; b=owGbwMvMwCRo6H6F97bub03G02pJDJl/P6bX5e598cfxQujj/d/9NhlFL5V6Pude5ZKrf3rcn ytsYPxV0hHLwiDIxCArpsjyZRvP0f0VhxS9DG1Pw8xhZQIZwsDFKQATebSOYX7BQ5MfS13Yvr/b ySG5OfFs1/Tz7rYM8yx8t66Z3nRNXCLlitTxjb8VzsxfrAIA 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: ublk: fix NULL pointer dereference in ublk_ctrl_set_size() ublk_ctrl_set_size() unconditionally dereferences ub->ub_disk via set_capacity_and_notify() without checking if it is NULL. ub->ub_disk is NULL before UBLK_CMD_START_DEV completes (it is only assigned in ublk_ctrl_start_dev()) and after UBLK_CMD_STOP_DEV runs (ublk_detach_disk() sets it to NULL). Since the UBLK_CMD_UPDATE_SIZE handler performs no state validation, a user can trigger a NULL pointer dereference by sending UPDATE_SIZE to a device that has been added but not yet started, or one that has been stopped. Fix this by checking ub->ub_disk under ub->mutex before dereferencing it, and returning -ENODEV if the disk is not available. The Linux kernel CVE team has assigned CVE-2026-43364 to this issue. Affected and fixed versions =========================== Issue introduced in 6.16 with commit 98b995660bff011d8e00af03abd74ac7d1ac1390 and fixed in 6.18.20 with commit f13fe6794726755a43090cb680c4c58cea6aa5f1 Issue introduced in 6.16 with commit 98b995660bff011d8e00af03abd74ac7d1ac1390 and fixed in 6.19.9 with commit c28d945bfa92e15147e93b73f95345b9bec979b0 Issue introduced in 6.16 with commit 98b995660bff011d8e00af03abd74ac7d1ac1390 and fixed in 7.0 with commit 25966fc097691e5c925ad080f64a2f19c5fd940a 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-2026-43364 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/block/ublk_drv.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/f13fe6794726755a43090cb680c4c58cea6aa5f1 https://git.kernel.org/stable/c/c28d945bfa92e15147e93b73f95345b9bec979b0 https://git.kernel.org/stable/c/25966fc097691e5c925ad080f64a2f19c5fd940a