{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64053", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.029Z", "datePublished": "2026-07-19T15:39:35.854Z", "dateUpdated": "2026-08-05T12:38:43.588Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:38:43.588Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: don't overwrite bip_vcnt in bio_integrity_copy_user()\n\nbio_integrity_add_page() already sets bip_vcnt to 1 for the bounce\nsegment. Overwriting it with nr_vecs breaks bip_vcnt <= bip_max_vcnt\non WRITE (bip_max_vcnt is 1), so the gap-merge checks in block/blk.h\nread past the bip_vec[] flex array. On READ the read is in bounds\nbut lands on a saved user bvec instead of the bounce.\n\nThe line was added for split propagation, but bio_integrity_clone()\ndoesn't copy bip_vcnt and BIP_CLONE_FLAGS excludes BIP_COPY_USER." } ], "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 bug is only reachable via local syscalls on an integrity-capable block device—io_uring read/write with PI attributes (`IOCB_HAS_METADATA` → `bio_integrity_map_iter()`) or NVMe ioctls (`NVME_IOCTL_SUBMIT_IO`/`NVME_IOCTL_IO_CMD` → `blk_rq_integrity_map_user()`). No network-facing server path (ksmbd, nfsd, nvmet) calls `bio_integrity_copy_user()`.\nAC:L - An attacker fully controls the conditions needed to hit the copy path and trigger the bad index: misaligned or multi-segment integrity user buffers force `copy=true`, multi-page scatter yields `nr_bvecs>1`, and concurrent O_DIRECT integrity writes to the same queue trigger `integrity_req_gap_*_merge()` that dereferences the corrupted `bip_vcnt`.\nPR:L - No kernel capabilities or init-namespace root are required beyond permission to open and perform O_DIRECT I/O on an integrity-enabled block device (`/dev/nvme*`, SCSI DIF disk); io_uring and NVMe ioctls are available to any local user granted device access (e.g., disk group, container volume mounts on storage nodes).\nUI:N - Exploitation is self-initiated by the attacker issuing crafted integrity I/O; no victim interaction such as mounting a filesystem or opening a file is required.\nS:U - Impact is confined to kernel memory safety within the block-integrity path on the host; it does not cross a VM, IOMMU, or sandbox security boundary.\nC:H - On WRITE, `bip_vcnt` is incorrectly set to `nr_vecs` while `bip_max_vcnt` is 1, so `integrity_req_gap_back_merge()`/`integrity_req_gap_front_merge()` in `block/blk.h` index `bip_vec[bip_vcnt-1]` past the single-slot kmalloc flex array, causing an out-of-bounds read of adjacent kernel heap memory that can disclose kernel pointers and other sensitive data.\nI:H - The corrupted `bip_vcnt` breaks integrity metadata bookkeeping during bio/request merging; on READ it causes gap-merge logic to consult saved user bvecs instead of the kernel bounce buffer, and the heap OOB read corrupts kernel memory-safety invariants in ways that can be chained toward further memory corruption or control-flow manipulation.\nA:H - With large `nr_bvecs` (up to `BIO_MAX_VECS`), the out-of-bounds `bip_vec` access can extend far beyond the kmalloc object boundary and provoke a kernel oops/page fault during merge processing; even without full exploitation, the integrity path malfunction can destabilize the I/O stack." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/bio-integrity.c" ], "versions": [ { "version": "3991657ae7074c3c497bf095093178bed37ea1b4", "lessThan": "d18160c9525c63c203656fefd847e94b538cd4a4", "status": "affected", "versionType": "git" }, { "version": "3991657ae7074c3c497bf095093178bed37ea1b4", "lessThan": "0d48654af4d1390c888389206cc13b51b82c30e6", "status": "affected", "versionType": "git" }, { "version": "3991657ae7074c3c497bf095093178bed37ea1b4", "lessThan": "066be1439593a381b1a29663becfcfe0c92363e7", "status": "affected", "versionType": "git" }, { "version": "3991657ae7074c3c497bf095093178bed37ea1b4", "lessThan": "637ad3a56a3b889527d1dacea6fea2a8bd648140", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "block/bio-integrity.c" ], "versions": [ { "version": "6.11", "status": "affected" }, { "version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.34", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.11", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "6.11", "versionEndExcluding": "6.12.92" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.34" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.0.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d18160c9525c63c203656fefd847e94b538cd4a4" }, { "url": "https://git.kernel.org/stable/c/0d48654af4d1390c888389206cc13b51b82c30e6" }, { "url": "https://git.kernel.org/stable/c/066be1439593a381b1a29663becfcfe0c92363e7" }, { "url": "https://git.kernel.org/stable/c/637ad3a56a3b889527d1dacea6fea2a8bd648140" } ], "title": "block: don't overwrite bip_vcnt in bio_integrity_copy_user()", "x_generator": { "engine": "bippy-1.2.0" } } } }