{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38333", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.005Z", "datePublished": "2025-07-10T08:15:05.768Z", "dateUpdated": "2026-08-05T12:01:11.722Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:01:11.722Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to bail out in get_new_segment()\n\n------------[ cut here ]------------\nWARNING: CPU: 3 PID: 579 at fs/f2fs/segment.c:2832 new_curseg+0x5e8/0x6dc\npc : new_curseg+0x5e8/0x6dc\nCall trace:\n new_curseg+0x5e8/0x6dc\n f2fs_allocate_data_block+0xa54/0xe28\n do_write_page+0x6c/0x194\n f2fs_do_write_node_page+0x38/0x78\n __write_node_page+0x248/0x6d4\n f2fs_sync_node_pages+0x524/0x72c\n f2fs_write_checkpoint+0x4bc/0x9b0\n __checkpoint_and_complete_reqs+0x80/0x244\n issue_checkpoint_thread+0x8c/0xec\n kthread+0x114/0x1bc\n ret_from_fork+0x10/0x20\n\nget_new_segment() detects inconsistent status in between free_segmap\nand free_secmap, let's record such error into super block, and bail\nout get_new_segment() instead of continue using the segment." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - get_new_segment() is reached only through the f2fs allocator on a locally mounted volume — ordinary writes, fsync, GC, or the background checkpoint thread; there is no network-facing consumer of this code.\nAC:L - Once the free_segmap/free_secmap divergence exists — from attacker-supplied on-disk metadata on removable f2fs media or the in-kernel state divergence observed in the field — the condition is hit deterministically on the next allocation from that section, with no race window or memory layout the attacker must win.\nPR:L - On an already-mounted f2fs volume (Android /data, auto-mounted SD/USB), any unprivileged local user with write access drives segment allocation via normal file writes and fsync; no capability or CAP_SYS_ADMIN is needed for the trigger itself.\nUI:N - The reported failure fires on the background checkpoint kthread during ordinary operation on an already-mounted filesystem, and removable f2fs media are auto-mounted by vold/udisks2 without any action by another user.\nS:U - The corruption is confined to the kernel/f2fs security authority on the same host; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The already-in-use segment is handed out as a new current segment starting at block offset 0, so the same physical blocks become mapped by two different inodes and a reader of one file obtains blocks written for another user's file on a shared filesystem.\nI:H - Live data and node blocks belonging to other files are physically overwritten, SIT valid_blocks/cur_valid_map are corrupted, and the underflowed free_segments count is persisted into the on-disk checkpoint (ckpt->free_segment_count is never validated on read), so the damage survives reboot.\nA:H - With CONFIG_F2FS_CHECK_FS the f2fs_bug_on is a plain BUG_ON taken while holding free_i->segmap_lock on the checkpoint kthread — an immediate panic; otherwise the free_segments/free_sections underflow defeats GC accounting and the downstream f2fs_bug_on()s and -ENOSPC path end in f2fs_stop_checkpoint(), shutting the filesystem down." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/segment.c", "include/linux/f2fs_fs.h" ], "versions": [ { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "f0023d7a2a86999c8e1300e911d92f995a5310a8", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "ca860f507a61c7c3d4dde47b830a5c0d555cf83c", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "bb5eb8a5b222fa5092f60d5555867a05ebc3bdf2", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/segment.c", "include/linux/f2fs_fs.h" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.35", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.4", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.12.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.15.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.16" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f0023d7a2a86999c8e1300e911d92f995a5310a8" }, { "url": "https://git.kernel.org/stable/c/ca860f507a61c7c3d4dde47b830a5c0d555cf83c" }, { "url": "https://git.kernel.org/stable/c/bb5eb8a5b222fa5092f60d5555867a05ebc3bdf2" } ], "title": "f2fs: fix to bail out in get_new_segment()", "x_generator": { "engine": "bippy-1.2.0" } } } }