{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64324", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.780Z", "datePublished": "2026-07-25T08:49:52.063Z", "dateUpdated": "2026-08-17T04:53:26.109Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:53:26.109Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nudf: validate free block extents against the partition length\n\nudf_free_blocks() checks the logical block number and count against the\npartition length, but drops the extent offset from that final bound. A\ncrafted extent can pass the guard while logicalBlockNum + offset + count\npoints past the partition, which later indexes past the space bitmap\narray.\n\nA single ftruncate(2) on a file backed by such an extent reliably\npanics the kernel. This is a local availability issue. On desktop\nsystems where UDisks/polkit allows the active user to mount removable\nUDF media without CAP_SYS_ADMIN, an unprivileged local user can supply\nthe crafted filesystem and trigger the panic by truncating a writable\nfile on it. Systems that require root or CAP_SYS_ADMIN to mount the\nimage have a higher prerequisite.\n\nNo confidentiality or integrity impact is claimed: the reproduced\nprimitive is an out-of-bounds read of a bitmap pointer slot followed by\na kernel panic.\n\nUse the already computed logicalBlockNum + offset + count value for the\npartition length check. Also make load_block_bitmap() reject an\nout-of-range block group before indexing s_block_bitmap[], so corrupted\ncallers cannot walk past the flexible array." } ], "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 - The flaw is reached through a local ftruncate(2) on a crafted, mounted UDF filesystem; no network protocol reaches this path.\nAC:L - The attacker controls the malicious extent and truncation offset, and a single ftruncate(2) reliably triggers the fault without a race or uncontrollable condition.\nPR:L - UDF cannot be mounted through an unprivileged user namespace, but default [UDisks policy](https://storaged.org/doc/udisks2-api/latest/udisks-polkit-ac tions.html) permits an active unprivileged user to mount removable media without administrator authentication.\nUI:N - The attacking local user can mount the supplied removable filesystem and truncate its writable file directly; no separate victim action is required.\nS:U - The vulnerable UDF code and the affected kernel resources remain within the host kernel's security authority; ordinary kernel privilege escalation does not change scope.\nC:H - Although the reproduced path is an out-of-bounds pointer-slot read followed by panic, a zero-valued out-of-range slot causes read_block_bitmap() to write a buffer_head pointer through that attacker-selected slot. Under the required higher-severity rule, this exploitable kernel heap corruption can enable code execution and unrestricted disclosure.\nI:H - The conditional out-of-bounds buffer_head pointer store corrupts kernel heap memory at an attacker-selected array index and can potentially alter control-relevant objects. This supports control-flow hijacking or arbitrary modification under the required higher-severity assumption.\nA:H - The [upstream report](https://lkml.iu.edu/2605.1/15216.html) confirms that one ftruncate(2) reliably panics the kernel, causing complete system unavailability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/udf/balloc.c" ], "versions": [ { "version": "934f815345c09c290a9b9a9cfdddc203ec2117e8", "lessThan": "fdd6229d2ae9914c1f25d1041db0f4f312a4fa76", "status": "affected", "versionType": "git" }, { "version": "22cc7323f090646c8cfb5939e6f15bdc2ed3fd27", "lessThan": "b54aee5652fcd7c23a0904a4623ec462c3edc70c", "status": "affected", "versionType": "git" }, { "version": "7c4fa9ebfce69619d132fe703dc2e2cf62a13723", "lessThan": "12af328d2ee8d68e81ba612246d0b54b22d23e1f", "status": "affected", "versionType": "git" }, { "version": "5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3", "lessThan": "fb49099206c5c57af28a157249fa7bcb5518f99e", "status": "affected", "versionType": "git" }, { "version": "56e69e59751d20993f243fb7dd6991c4e522424c", "lessThan": "9442d75429b0c556292a7454fe888d54259f5240", "status": "affected", "versionType": "git" }, { "version": "56e69e59751d20993f243fb7dd6991c4e522424c", "lessThan": "335202ab25b01fdd45889ff25eab70864686dea3", "status": "affected", "versionType": "git" }, { "version": "56e69e59751d20993f243fb7dd6991c4e522424c", "lessThan": "be87de7789a82a030a4896bc7683415ec9fa6f2b", "status": "affected", "versionType": "git" }, { "version": "56e69e59751d20993f243fb7dd6991c4e522424c", "lessThan": "5f0419457f89dce1a3f1c8e62a3adf2f39ab8168", "status": "affected", "versionType": "git" }, { "version": "097420e48e30f51e8f4f650b5c946f5af63ec1a3", "status": "affected", "versionType": "git" }, { "version": "5def895b42ef16a2da6402818cba8d7ec8ede1ef", "status": "affected", "versionType": "git" }, { "version": "05fb2bf477d3fe5421bd4cb699574737f52bd88b", "status": "affected", "versionType": "git" }, { "version": "5.10.224", "lessThan": "5.10.261", "status": "affected", "versionType": "semver" }, { "version": "5.15.165", "lessThan": "5.15.212", "status": "affected", "versionType": "semver" }, { "version": "6.1.105", "lessThan": "6.1.178", "status": "affected", "versionType": "semver" }, { "version": "6.6.46", "lessThan": "6.6.145", "status": "affected", "versionType": "semver" }, { "version": "4.19.320", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.4.282", "lessThan": "5.5", "status": "affected", "versionType": "semver" }, { "version": "6.10.5", "lessThan": "6.11", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/udf/balloc.c" ], "versions": [ { "version": "6.11", "status": "affected" }, { "version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "5.10.224", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.165", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.105", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.46", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.320" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.282" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76" }, { "url": "https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c" }, { "url": "https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f" }, { "url": "https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e" }, { "url": "https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240" }, { "url": "https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3" }, { "url": "https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b" }, { "url": "https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168" } ], "title": "udf: validate free block extents against the partition length", "x_generator": { "engine": "bippy-1.2.0" } } } }