{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-63812", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-63812" ], "published": "2026-07-19T12:02:32Z", "summary": "f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node()", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node()\n\nWhen __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does\nnot reset the length of the largest extent to 0 and update the inode\nfolio. Since modifications to the extent tree are disallowed afterward,\nthe cached largest extent may become stale. This can trigger the\nfollowing error in xfstests generic/388:\n\nF2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix\n\nIn the f2fs_drop_inode path, __destroy_extent_node() does not need to\nguarantee that et->node_cnt is 0, because concurrency with writeback\nis expected in this path, and writeback may update the extent cache.\n\nThis patch reverts commit ed78aeebef05 (\"f2fs: fix node_cnt race between\nextent node destroy and writeback\"), and remove the unnecessary zero\ncheck of et->node_cnt.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.12.93-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.93+rpt-rpi-2712", "binary_version": "1:6.12.93-1+rpt1" }, { "binary_name": "linux-image-6.12.93+rpt-rpi-v6", "binary_version": "1:6.12.93-1+rpt1" }, { "binary_name": "linux-image-6.12.93+rpt-rpi-v7", "binary_version": "1:6.12.93-1+rpt1" }, { "binary_name": "linux-image-6.12.93+rpt-rpi-v7l", "binary_version": "1:6.12.93-1+rpt1" }, { "binary_name": "linux-image-6.12.93+rpt-rpi-v8", "binary_version": "1:6.12.93-1+rpt1" }, { "binary_name": "linux-image-6.12.93+rpt-rpi-v8-rt", "binary_version": "1:6.12.93-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.12.93-1+rpt1": { "linux_commit": "d8ab4e908235da7727f22dd36ad5af224671677d", "upstream_version": "6.12.93", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.95" } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.18.33-1+rpt1", "1:6.18.34-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.18.33+rpt-rpi-2712", "binary_version": "1:6.18.33-1+rpt1" }, { "binary_name": "linux-image-6.18.33+rpt-rpi-v6", "binary_version": "1:6.18.33-1+rpt1" }, { "binary_name": "linux-image-6.18.33+rpt-rpi-v7", "binary_version": "1:6.18.33-1+rpt1" }, { "binary_name": "linux-image-6.18.33+rpt-rpi-v8", "binary_version": "1:6.18.33-1+rpt1" }, { "binary_name": "linux-image-6.18.33+rpt-rpi-v8-rt", "binary_version": "1:6.18.33-1+rpt1" }, { "binary_name": "linux-image-6.18.34+rpt-rpi-2712", "binary_version": "1:6.18.34-1+rpt1" }, { "binary_name": "linux-image-6.18.34+rpt-rpi-v6", "binary_version": "1:6.18.34-1+rpt1" }, { "binary_name": "linux-image-6.18.34+rpt-rpi-v7", "binary_version": "1:6.18.34-1+rpt1" }, { "binary_name": "linux-image-6.18.34+rpt-rpi-v8", "binary_version": "1:6.18.34-1+rpt1" }, { "binary_name": "linux-image-6.18.34+rpt-rpi-v8-rt", "binary_version": "1:6.18.34-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.18.33-1+rpt1": { "linux_commit": "95b85bebbedcaedfa7ca79116ed38b7376fba412", "upstream_version": "6.18.33", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.18.38" }, "1:6.18.34-1+rpt1": { "linux_commit": "c8c7494100e99ee05b11aaa4f0588a223a63d1af", "upstream_version": "6.18.34", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.18.38" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-63812" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/7e4d8f98be63f98856a5176b9188dada6e7ba9ee" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/58a5deb220bcac4c73bf58954c0845644c997487" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/20190e498057997532c7f186d081011f18e0a462" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/edf12cbeeeabe799bd2ee21fdb5c336cce6fbad7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/1f70ddb28a3c71df124da5fa4040c808116d6bb9" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-17T05:24:08Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - The bug is reached only through local VFS filesystem activity (write, unlink, concurrent writeback) on an F2FS mount, most severely on Android/embedded userdata partitions where F2FS is the default local filesystem.\nAC:L - An attacker can reliably orchestrate the inode-eviction/writeback race by unlinking files while writeback is in progress on the same inode, controlling both sides of the concurrency window.\nPR:L - Triggering the race requires only unprivileged write access to files on a mounted F2FS filesystem (e.g., creating, writing, and unlinking files in one's own directory on Android /data), not real root or CAP_SYS_ADMIN.\nUI:N - Exploitation requires no action from a separate victim; the attacker drives the file I/O and unlink operations that provoke the stale extent-cache state.\nS:U - Impact is confined to kernel/filesystem integrity on the affected host; there is no cross-security-authority boundary such as VM escape or container-to-host breakout.\nC:H - Stale largest-extent metadata persisted to the on-disk inode can cause subsequent reads (after inode reload or inode-number reuse) to map logical file offsets to wrong physical blocks, disclosing data from other files or freed blocks.\nI:H - Incorrect on-disk extent metadata corrupts the inode-to-block mapping and can cause wrong data blocks to be associated with a file, constituting exploitable filesystem metadata corruption with integrity impact beyond a simple crash.\nA:H - The stale cache triggers sanity_check_extent_cache failures (as seen in xfstests generic/388), f2fs_handle_error(ERROR_CORRUPTED_INODE), and potential kernel BUG_ON via f2fs_bug_on when CONFIG_F2FS_CHECK_FS is enabled, all causing denial of filesystem or kernel service." } } }