{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43006","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-05-01T14:12:55.974Z","datePublished":"2026-05-01T14:15:14.176Z","dateUpdated":"2026-08-05T12:25:13.184Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:25:13.184Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/rsrc: reject zero-length fixed buffer import\n\nvalidate_fixed_range() admits buf_addr at the exact end of the\nregistered region when len is zero, because the check uses strict\ngreater-than (buf_end > imu->ubuf + imu->len).  io_import_fixed()\nthen computes offset == imu->len, which causes the bvec skip logic\nto advance past the last bio_vec entry and read bv_offset from\nout-of-bounds slab memory.\n\nReturn early from io_import_fixed() when len is zero.  A zero-length\nimport has no data to transfer and should not walk the bvec array\nat all.\n\n  BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0\n  Read of size 4 at addr ffff888002bcc254 by task poc/103\n  Call Trace:\n   io_import_reg_buf+0x697/0x7f0\n   io_write_fixed+0xd9/0x250\n   __io_issue_sqe+0xad/0x710\n   io_issue_sqe+0x7d/0x1100\n   io_submit_sqes+0x86a/0x23c0\n   __do_sys_io_uring_enter+0xa98/0x1590\n  Allocated by task 103:\n  The buggy address is located 12 bytes to the right of\n   allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)"}],"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 vulnerable path is reached through local io_uring syscalls: create a ring, register a fixed buffer, then submit READ_FIXED or WRITE_FIXED. It is not reachable by remote packets or adjacent/physical input.\nAC:L - The trigger is deterministic: use len zero with buf_addr exactly at the end of a registered fixed buffer. No race or attacker-uncontrolled heap state is required to reach the out-of-bounds read.\nPR:L - An unprivileged local user can use io_uring when the upstream sysctl allows it, and buffer registration only requires ordinary user memory within resource limits. No real root or init-namespace capability is required.\nUI:N - After obtaining local execution, the attacker directly invokes io_uring_setup, io_uring_register, and io_uring_enter. No victim action is needed.\nS:U - The vulnerability is in the kernel servicing the attacker's local process and does not cross a separate security authority such as a VM host boundary. Standard local kernel compromise or crash remains Scope Unchanged.\nC:H - The bug performs an attacker-triggered out-of-bounds read from adjacent kernel slab memory while constructing the fixed-buffer bio_vec iterator. Under conservative kernel scoring, this is treated as high confidentiality impact because kernel heap data is read outside the valid object.\nI:N - The demonstrated primitive is an out-of-bounds read of bio_vec metadata, not an out-of-bounds write or use-after-free. I did not find a defensible direct data modification or control-flow overwrite primitive from this zero-length import.\nA:H - The reported path produces a KASAN slab-out-of-bounds BUG in io_import_reg_buf, and the same local trigger can be submitted repeatedly. Kernel oops/panic potential is High availability impact."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/rsrc.c"],"versions":[{"version":"8622b20f23ed165f48b8ca61503a107d17f8d585","lessThan":"040a1e7e0e2f01851fec1dd2d96906f8636a9f75","status":"affected","versionType":"git"},{"version":"8622b20f23ed165f48b8ca61503a107d17f8d585","lessThan":"40170fc1a79c1b2e68f09ae6aac687b7305ae6f4","status":"affected","versionType":"git"},{"version":"8622b20f23ed165f48b8ca61503a107d17f8d585","lessThan":"111a12b422a8cfa93deabaef26fec48237163214","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/rsrc.c"],"versions":[{"version":"6.15","status":"affected"},{"version":"0","lessThan":"6.15","status":"unaffected","versionType":"semver"},{"version":"6.18.22","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"6.19.12","lessThanOrEqual":"6.19.*","status":"unaffected","versionType":"semver"},{"version":"7.0","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":"6.15","versionEndExcluding":"6.18.22"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.19.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.0"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/040a1e7e0e2f01851fec1dd2d96906f8636a9f75"},{"url":"https://git.kernel.org/stable/c/40170fc1a79c1b2e68f09ae6aac687b7305ae6f4"},{"url":"https://git.kernel.org/stable/c/111a12b422a8cfa93deabaef26fec48237163214"}],"title":"io_uring/rsrc: reject zero-length fixed buffer import","x_generator":{"engine":"bippy-1.2.0"}}}}