{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80555", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.766Z", "datePublished": "2026-08-26T14:37:22.969Z", "dateUpdated": "2026-08-27T12:40:15.211Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-27T12:40:15.211Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio_ccw: Free all memory if cp_init() fails\n\nThe routine cp_free() is called to unpin/free any memory once an I/O\nis completed successfully, or if cp_prefetch() fails. But if cp_init()\nfails, and cp->initialized is not enabled, the same routine cannot be\nused to free all the memory.\n\nAn attempt to address this exists in ccwchain_handle_ccw(), where a\nsingle call to ccwchain_free() is made for the currently-processed\nCCW segment. But this will leak other segments (created as a result\nof a Transfer in Channel) that had been allocated as part of the same\nchannel program.\n\nAddress this by performing the cleanup outside of the recursive\nccwchain_handle_ccw()/ccwchain_loop_tic() logic." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is reached when userspace writes the vfio-ccw io_region (VFIO device mmap/write), triggering fsm_io_request() -> cp_init(); on s390 KVM this is driven by QEMU forwarding guest channel-I/O channel programs, requiring local VFIO/device interaction rather than any network protocol.\nAC:L - An attacker can deterministically fail cp_init() after allocating multiple TIC-linked ccwchain segments by crafting a channel program whose early TIC targets succeed and a later one fails (invalid CPA, chain-length/count limit, or dma_rw error), leaking prior segments on every attempt without races.\nPR:N - On s390 KVM with CCW passthrough, a malicious guest can submit crafted multi-TIC channel programs through normal guest I/O; QEMU forwards them to vfio-ccw without the attacker holding host CAP_SYS_ADMIN, root, or other real init-namespace privileges beyond the assigned device.\nUI:N - No victim interaction is required beyond the attacker (or their guest) issuing channel-I/O start requests with a malicious channel program; exploitation does not depend on another user mounting media, accepting prompts, or performing administrative actions at trigger time.\nS:C - The leaked ccwchain, CCW, and page_array allocations are host kernel slab memory; a guest VM triggering this through passthrough crosses the guest-host virtualization boundary by consuming host resources the guest security domain should not affect.\nC:N - This is a kernel memory leak on the cp_init() error path, not a use-after-free, out-of-bounds read, or other memory corruption; leaked objects are orphaned in kernel heap and are not returned to userspace or the guest, so no information disclosure occurs.\nI:N - The flaw only fails to free kernel allocations when cp_init() errors; it does not corrupt memory, modify guest or host data, or provide write or control-flow primitives, and cp->initialized stays false so cp_free() never runs on the error or close paths.\nA:H - Each failed cp_init() permanently orphans up to CCWCHAIN_COUNT_MAX ccwchain segments (large GFP_DMA allocations), and subsequent cp_init() calls INIT_LIST_HEAD without freeing prior leaks; repeated guest or VFIO I/O requests can exhaust host memory and cause system-wide OOM or severe denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/s390/cio/vfio_ccw_cp.c" ], "versions": [ { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "276bd7ed34d56c48c65c43c0b08f2ee77029b2fa", "status": "affected", "versionType": "git" }, { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "f9bcff265556796834122f95de16d52a8375206c", "status": "affected", "versionType": "git" }, { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "17e01e342af74de12899c206dcc9ec90684703aa", "status": "affected", "versionType": "git" }, { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "152fcb74a26804b70909381c6acc90595a0ae1c1", "status": "affected", "versionType": "git" }, { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "6a917199aaf97904f5619afe3dfdacb155b03e8c", "status": "affected", "versionType": "git" }, { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "32e3d364a7b8295120d37e6a6bd433d2de26f748", "status": "affected", "versionType": "git" }, { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "4699b54fada156534cbb39834d47fc9374d7a1f5", "status": "affected", "versionType": "git" }, { "version": "8b515be512a2435bb8aedc6390cbe140167f9eb9", "lessThan": "74186c2968f8f756ac3226b545b598457c910c75", "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/s390/cio/vfio_ccw_cp.c" ], "versions": [ { "version": "5.3", "status": "affected" }, { "version": "0", "lessThan": "5.3", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.267", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.218", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.185", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.154", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.105", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.46", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.10", "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": "5.3", "versionEndExcluding": "5.10.267" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "5.15.218" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.1.185" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.6.154" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.12.105" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.18.46" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.1.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/276bd7ed34d56c48c65c43c0b08f2ee77029b2fa" }, { "url": "https://git.kernel.org/stable/c/f9bcff265556796834122f95de16d52a8375206c" }, { "url": "https://git.kernel.org/stable/c/17e01e342af74de12899c206dcc9ec90684703aa" }, { "url": "https://git.kernel.org/stable/c/152fcb74a26804b70909381c6acc90595a0ae1c1" }, { "url": "https://git.kernel.org/stable/c/6a917199aaf97904f5619afe3dfdacb155b03e8c" }, { "url": "https://git.kernel.org/stable/c/32e3d364a7b8295120d37e6a6bd433d2de26f748" }, { "url": "https://git.kernel.org/stable/c/4699b54fada156534cbb39834d47fc9374d7a1f5" }, { "url": "https://git.kernel.org/stable/c/74186c2968f8f756ac3226b545b598457c910c75" } ], "title": "s390/vfio_ccw: Free all memory if cp_init() fails", "x_generator": { "engine": "bippy-1.2.0" } } } }