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 B87B9560ADE for ; Fri, 11 Sep 2026 19:47:42 +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=1789156078; cv=none; b=NSrZKVijk0H+WDkC6/LKAo2M4gu1B3aQM0MvmnUuypDOn7RzAt7eqYuQVMDwzFzT2PzN5R/WDhBcC2zAqp5rn0853SkaiV2FNaJAxBgJyb/kDMHN/QMTUnwJF/wHcNNkHG6wndPdbR9eSStzgUunUO9yg5hi5+ohmoebVUcw+Ik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156078; c=relaxed/simple; bh=6KM2mhmBfZ8F8g6o+cpoUbZoJfpVEEiYXyvm6So/coM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ucKM973AMzcYNynbjDSEeqFJjWbmJzxR0YpKXrFmf+nMcPhA0b3NYMML4gD86WXXAZZWu/kGWsCDVW0zl44VynbRuf1k1n5pBLGwqHOVNmwBP+R7LP0dUAbjP92d8WJ5hVYUGQkebBWEL9xa7A7JU8GnNh0DmpHgFazhO6XkPs4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Sf2hxiod; 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="Sf2hxiod" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0CD71F00898; Fri, 11 Sep 2026 19:47:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156058; bh=OG5l+JZFd5kaHn2+xhqerfa13YFSPkm/fDH5qAODbuU=; h=From:To:Cc:Subject:Date:Reply-To; b=Sf2hxiodAd1IEmE5Ch36hXE6vBuNdUwRx7ZI8zVqqFZ2nO9T/rYmwGoQPvgiSuYD4 3dmMLjx2SDBTtgyH0cnbJ0Sylql/nTpP2RKpOfVJOaStWzETGaits7a4v48gn7iVPB 52RsnZJRbOw39Cn7xNJPpWGcWGx/LvlZk9JEiVWs= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80956: dm-pcache: only hand out initialized cache segments Date: Fri, 11 Sep 2026 21:41:02 +0200 Message-ID: <2026091141-CVE-2026-80956-7841@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=2671; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=itf6/LEpkkLzPRVDSgez6NBHo6+PIw9etZDxoBY+Wf8=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIi1bQmqY9yw0C0voentXxND+TqERu+tpy97pPUf10 /Yq/XnTEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABOJcGOYn/p60bETpxcdCBb9 5Dy1m7mFy+22N8Nc8frAN3tfzn26fj1Plu5l+eqLa3dOBgA= 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: dm-pcache: only hand out initialized cache segments get_cache_segment() scans the segment map up to cache->n_segs, the physical device segment count, but cache_segs_init() only initializes the first cache_info->n_segs segments. A crafted image with cache_info->n_segs smaller than the device count leaves the remaining pcache_cache_segment structs zeroed (segment.data == NULL), and the allocator can hand one to cache_kset_close(), which writes through the returned segment's data pointer with no NULL check. Bound the allocator's search to cache_info->n_segs so only initialized segments are ever returned. A conforming cache sets n_segs equal to the device segment count, so this rejects nothing legitimate. The Linux kernel CVE team has assigned CVE-2026-80956 to this issue. Affected and fixed versions =========================== Issue introduced in 6.18 with commit 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 and fixed in 6.18.50 with commit 83e3116283ed2c6a6a1fa662862a4b4d7d2701a2 Issue introduced in 6.18 with commit 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 and fixed in 7.2.4 with commit 692037ae1a7cfacc2f0c22c6e034c1dfee0e553f Issue introduced in 6.18 with commit 1d57628ff95b32d5cfa8d8f50e07690c161e9cf0 and fixed in 7.3-rc1 with commit 2df0fc042e299bae3c0f60ea5cd2af9285658e9f 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-2026-80956 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/md/dm-pcache/cache_segment.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/83e3116283ed2c6a6a1fa662862a4b4d7d2701a2 https://git.kernel.org/stable/c/692037ae1a7cfacc2f0c22c6e034c1dfee0e553f https://git.kernel.org/stable/c/2df0fc042e299bae3c0f60ea5cd2af9285658e9f