{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80958", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.809Z", "datePublished": "2026-09-11T19:42:25.861Z", "dateUpdated": "2026-10-19T08:45:42.221Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:45:42.221Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm-pcache: clamp the tail kset read to the segment data region\n\nThe tail-kset read in cache_replay(), the writeback worker and the GC\nworker bounds its length by PCACHE_SEG_SIZE - seg_off, the raw segment\nsize rather than the data region. A tail near the segment end reads past\nthe segment data into the following control area.\n\nClamp the read to cache_seg_remain(), the data region." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The over-read is reached only through local device-mapper ioctls on /dev/mapper/control (ctl_ioctl requires CAP_SYS_ADMIN, then table_load → dm_pcache_ctr → pcache_cache_start → cache_replay), and later via the writeback and GC workers on that mapped device; no network, Bluetooth, or physical-bus input reaches the kset copy.\nAC:L - An attacker who supplies a crafted DAX/pmem cache image fully controls the persisted key_tail and dirty_tail, so placing a tail near the segment end deterministically copies past data_size; no race, heap layout, or other victim state outside attacker control is required.\nPR:L - dm-ioctl.c gates table load with capable(CAP_SYS_ADMIN), which user-namespace and privileged-container administrators satisfy without init-namespace root; the attacker can attach a DAX cache device they control and load the pcache table themselves.\nUI:N - Exploitation requires only the attacker's own dmsetup/DM_TABLE_LOAD of a crafted pcache cache device; no separate victim must mount media, open files, or take any other action.\nS:U - The out-of-bounds kset read and any resulting kernel oops remain inside the host kernel device-mapper/pcache subsystem; this is not a VM escape, IOMMU bypass, or other cross-authority breakout.\nC:H - copy_mc_to_kernel() copies up to PCACHE_KSET_ONMEDIA_SIZE_MAX (~5 KiB) past segment data_size into the next segment's control area, and on the last segment that continues beyond the DAX mapping into adjacent kernel memory; out-of-bounds reads are High unless limited to a few bytes.\nI:N - The destination is a correctly sized kset buffer (kzalloc or the writeback/GC scratch arrays); this is a source over-read, not an out-of-bounds write, use-after-free, or other kernel-memory corruption or control-flow hijack primitive.\nA:H - Reading past the last DAX-mapped page hits a vmap guard or unmapped hole and oopses the kernel, and a CRC-valid kset assembled across the data/control boundary that is larger than cache_seg_remain() hits BUG_ON in cache_pos_advance(), crashing the host." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/md/dm-pcache/cache_gc.c", "drivers/md/dm-pcache/cache_key.c", "drivers/md/dm-pcache/cache_writeback.c" ], "versions": [ { "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0", "lessThan": "2cd9776fe3f2d88ec22c36d3c8ba09fbf9d5500c", "status": "affected", "versionType": "git" }, { "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0", "lessThan": "1ab55354368d071ebaee4d8c82313955eab65a04", "status": "affected", "versionType": "git" }, { "version": "1d57628ff95b32d5cfa8d8f50e07690c161e9cf0", "lessThan": "becf07e2b0053027495ecd671b1f82fb2e615f68", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/md/dm-pcache/cache_gc.c", "drivers/md/dm-pcache/cache_key.c", "drivers/md/dm-pcache/cache_writeback.c" ], "versions": [ { "version": "6.18", "status": "affected" }, { "version": "0", "lessThan": "6.18", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "6.18", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2cd9776fe3f2d88ec22c36d3c8ba09fbf9d5500c" }, { "url": "https://git.kernel.org/stable/c/1ab55354368d071ebaee4d8c82313955eab65a04" }, { "url": "https://git.kernel.org/stable/c/becf07e2b0053027495ecd671b1f82fb2e615f68" } ], "title": "dm-pcache: clamp the tail kset read to the segment data region", "x_generator": { "engine": "bippy-1.2.0" } } } }