{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31447", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.091Z", "datePublished": "2026-04-22T13:53:43.467Z", "dateUpdated": "2026-08-05T12:22:37.767Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:22:37.767Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: reject mount if bigalloc with s_first_data_block != 0\n\nbigalloc with s_first_data_block != 0 is not supported, reject mounting\nit." } ], "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 ext4 code is reached through local filesystem mount and file-operation paths on an attacker-controlled ext4 image or block device, not through a network protocol.\nAC:L - The attacker controls the filesystem geometry and extent layout, and the reported trigger is deterministic after mounting and operating on the crafted filesystem; no race or external timing condition is required.\nPR:N - Direct mounting is gated by CAP_SYS_ADMIN in the initial user namespace because ext4 lacks FS_USERNS_MOUNT, but in the attacker-supplied filesystem scenario the privileged mount is performed by the victim or system automounter. The attacker does not need their own kernel privileges.\nUI:R - Exploitation requires a victim or privileged mounting path to mount the crafted ext4 filesystem and perform an operation such as unlink/truncate on it.\nS:U - The impact remains within the kernel/filesystem security authority; this is not a VM escape, IOMMU bypass, or cross-scope boundary violation.\nC:H - The bug is a use-after-free in ext4 extent metadata handling, and UAF conditions can expose reused memory contents or be shaped into broader kernel information disclosure.\nI:H - The faulty cluster arithmetic can free and reuse metadata blocks still referenced by extents, creating memory/filesystem metadata corruption that is defensibly exploitable for high-integrity impact.\nA:H - The observed failure is a KASAN use-after-free in ext4_ext_remove_space and can crash or destabilize the kernel, giving high availability impact." } ] } ], "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": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "5ad6d994255e27a3254079dfb50ca861fc31f2d0", "status": "affected", "versionType": "git" }, { "version": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "3a926957cc95899ef88529710836edadc03c71a1", "status": "affected", "versionType": "git" }, { "version": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "7b58c110b4e1f028eb38eec9ed3555e9be81c8b0", "status": "affected", "versionType": "git" }, { "version": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "b77de3fceafbb39f30e4ff5dc986f863d5456417", "status": "affected", "versionType": "git" }, { "version": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "d787d3ae96648dc14a3b7ca8fde817177e82c1c7", "status": "affected", "versionType": "git" }, { "version": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "ad1f6d608f33f59d21a3d025615d6786a6443998", "status": "affected", "versionType": "git" }, { "version": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "7d5b04290156c3fc316eecc86a4f9d201ab7d44a", "status": "affected", "versionType": "git" }, { "version": "281b59959707dfae03ce038cdf231bf4904e170c", "lessThan": "3822743dc20386d9897e999dbb990befa3a5b3f8", "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": "3.2", "status": "affected" }, { "version": "0", "lessThan": "3.2", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.253", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.168", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.131", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.80", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.21", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.11", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "3.2", "versionEndExcluding": "5.10.253" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.1.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.6.131" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.12.80" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.18.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.19.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5ad6d994255e27a3254079dfb50ca861fc31f2d0" }, { "url": "https://git.kernel.org/stable/c/3a926957cc95899ef88529710836edadc03c71a1" }, { "url": "https://git.kernel.org/stable/c/7b58c110b4e1f028eb38eec9ed3555e9be81c8b0" }, { "url": "https://git.kernel.org/stable/c/b77de3fceafbb39f30e4ff5dc986f863d5456417" }, { "url": "https://git.kernel.org/stable/c/d787d3ae96648dc14a3b7ca8fde817177e82c1c7" }, { "url": "https://git.kernel.org/stable/c/ad1f6d608f33f59d21a3d025615d6786a6443998" }, { "url": "https://git.kernel.org/stable/c/7d5b04290156c3fc316eecc86a4f9d201ab7d44a" }, { "url": "https://git.kernel.org/stable/c/3822743dc20386d9897e999dbb990befa3a5b3f8" } ], "title": "ext4: reject mount if bigalloc with s_first_data_block != 0", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:47:53.009Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", 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