{"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"}}}}