{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40198", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.178Z", "datePublished": "2025-11-12T21:56:33.220Z", "dateUpdated": "2026-08-05T12:08:27.771Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:08:27.771Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: avoid potential buffer over-read in parse_apply_sb_mount_options()\n\nUnlike other strings in the ext4 superblock, we rely on tune2fs to\nmake sure s_mount_opts is NUL terminated. Harden\nparse_apply_sb_mount_options() by treating s_mount_opts as a potential\n__nonstring." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable code is reached only through `__ext4_fill_super()` during the `mount(2)` syscall path, requiring local access to attach the crafted ext4 image (loop device, disk file, or removable media). There is no network-facing path to `parse_apply_sb_mount_options()`.\nAC:L - The attacker fully controls the on-disk superblock and merely has to fill all 64 bytes of `s_mount_opts` with non-NUL data to defeat the termination assumption; no race, no timing, no memory-layout condition outside the attacker's control.\nPR:N - The attacker needs no account or privilege on the target system — they only supply the malicious filesystem image (USB stick, disk file, virtual disk), and the privileged mount is performed by the victim or by an automounter such as udisks2 on desktops and kiosks.\nUI:R - A user or automounter must actually mount the attacker-supplied ext4 filesystem, since `ext4_fs_type` lacks `FS_USERNS_MOUNT` and the code path runs only at `ext4_fill_super()` time.\nS:U - The over-read and its consequences are confined to the kernel's own memory and the mounting host's security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - An unterminated `s_mount_opts` causes reads past the 64-byte field into adjacent superblock-buffer and page memory, and on parse failure `ext4_msg()` prints the resulting string verbatim into the kernel log, disclosing out-of-bounds kernel memory; the read is not bounded to a few bytes.\nI:H - The over-read bytes are handed to `parse_options()` and `ext4_apply_options()`, so uncontrolled out-of-bounds kernel memory determines mount state such as journal mode, error behavior, and quota file names on the newly mounted filesystem.\nA:H - With a 1024-byte block buffer at the end of a page, the over-read can walk into unmapped memory and oops the kernel, and on KASAN/hardened builds the out-of-bounds access panics the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/ext4/super.c" ], "versions": [ { "version": "8b67f04ab9de5d8f3a71aef72bf02c995a506db5", "lessThan": "7bf46ff83a0ef11836e38ebd72cdc5107209342d", "status": "affected", "versionType": "git" }, { "version": "8b67f04ab9de5d8f3a71aef72bf02c995a506db5", "lessThan": "b2bac84fde28fb6a88817b8b761abda17a1d300b", "status": "affected", "versionType": "git" }, { "version": "8b67f04ab9de5d8f3a71aef72bf02c995a506db5", "lessThan": "e651294218d2684302ee5ed95ccf381646f3e5b4", "status": "affected", "versionType": "git" }, { "version": "8b67f04ab9de5d8f3a71aef72bf02c995a506db5", "lessThan": "01829af7656b56d83682b3491265d583d502e502", "status": "affected", "versionType": "git" }, { "version": "8b67f04ab9de5d8f3a71aef72bf02c995a506db5", "lessThan": "2a0cf438320cdb783e0378570744c0ef0d83e934", "status": "affected", "versionType": "git" }, { "version": "8b67f04ab9de5d8f3a71aef72bf02c995a506db5", "lessThan": "a6e94557cd05adc82fae0400f6e17745563e5412", "status": "affected", "versionType": "git" }, { "version": "8b67f04ab9de5d8f3a71aef72bf02c995a506db5", "lessThan": "8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8", "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/ext4/super.c" ], "versions": [ { "version": "2.6.36", "status": "affected" }, { "version": "0", "lessThan": "2.6.36", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.301", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.246", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.158", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.114", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.54", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.4", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "2.6.36", "versionEndExcluding": "5.4.301" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "5.10.246" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.1.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.6.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.12.54" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.17.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7bf46ff83a0ef11836e38ebd72cdc5107209342d" }, { "url": "https://git.kernel.org/stable/c/b2bac84fde28fb6a88817b8b761abda17a1d300b" }, { "url": "https://git.kernel.org/stable/c/e651294218d2684302ee5ed95ccf381646f3e5b4" }, { "url": "https://git.kernel.org/stable/c/01829af7656b56d83682b3491265d583d502e502" }, { "url": "https://git.kernel.org/stable/c/2a0cf438320cdb783e0378570744c0ef0d83e934" }, { "url": "https://git.kernel.org/stable/c/a6e94557cd05adc82fae0400f6e17745563e5412" }, { "url": "https://git.kernel.org/stable/c/8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8" } ], "title": "ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()", "x_generator": { "engine": "bippy-1.2.0" } } } }