{"id":"CVE-2026-80811","title":"io_uring/cmd: fix iovec leak when the async cmd is not recycled","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/cmd: fix iovec leak when the async cmd is not recycled\n\nAn io_async_cmd carries an iovec array in ->vec.iovec, allocated when the\nvec has to grow and kept acro…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < b6a768aa975b9ca81b92f028bdd975d1f8237894","Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < b290de4d16d75b6c1ef42025b47f5d94eb1ec09f","Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < 7068d3587a64a24943a7c9e232976da2c9e0e303","Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1","Linux 6.15"],"published":"2026-09-04","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:44:04.686Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80811","references":[{"url":"https://git.kernel.org/stable/c/b6a768aa975b9ca81b92f028bdd975d1f8237894"},{"url":"https://git.kernel.org/stable/c/b290de4d16d75b6c1ef42025b47f5d94eb1ec09f"},{"url":"https://git.kernel.org/stable/c/7068d3587a64a24943a7c9e232976da2c9e0e303"},{"url":"https://git.kernel.org/stable/c/bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1"}],"tags":["cve.org"],"epss":0.00209,"epssPercentile":0.10306,"ingestedAt":"2026-10-19T09:16:01.508Z","slug":"CVE-2026-80811","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/cmd: fix iovec leak when the async cmd is not recycled\n\nAn io_async_cmd carries an iovec array in ->vec.iovec, allocated when the\nvec has to grow and kept across recycling through ctx->cmd_cache.  On two\npaths nothing frees it and io_clean_op()'s kfree(req->async_data) drops\nthe io_async_cmd without it.\n\nio_req_uring_cleanup() clears the async data flags only when\nio_alloc_cache_put() succeeds, and the cache holds IO_ALLOC_CACHE_MAX ==\n128 entries, so once it is full the put fails and the vec is left behind.\nAn NVMe passthrough workload gets there without doing anything unusual:\nnvme_uring_cmd_io() returns -EIOCBQUEUED, so the io_async_cmd stays\nattached for the lifetime of the command and the live object count tracks\nthe queue depth.  Above 128 the puts start failing.\n\n->cleanup is the last chance to free an inherited vec, since\nio_req_uring_cleanup() returns early for an io-wq issued command and is\nnot called at all for one completed without ever being issued.  But\nio_clean_op() calls ->cleanup only if REQ_F_NEED_CLEANUP is set, and for\nuring_cmd that happens only where the vec has to grow, so a command\nreusing a large enough cached vec never sets it.  io_rw_alloc_async() and\nio_msg_alloc_async() flag an inherited vec for exactly this reason;\nio_uring_cmd_prep() does not.\n\nFlag an inherited vec in io_uring_cmd_prep(), and free the vec when the\ncache put fails, as io_req_rw_cleanup() does.\n\nThe leak is invisible under KASAN, where io_alloc_cache_vec_kasan() frees\nthe vec unconditionally.\n\n## Affected\n\n- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < b6a768aa975b9ca81b92f028bdd975d1f8237894`\n- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < b290de4d16d75b6c1ef42025b47f5d94eb1ec09f`\n- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < 7068d3587a64a24943a7c9e232976da2c9e0e303`\n- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1`\n- `Linux 6.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}