CVE-2026-81009

linux: In the Linux kernel, the following vulnerability has been resolved: io_uring/query: cap user size passed to copy_str...

CVE-2026-81009 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-81009, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
n/a
important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
n/a

In the Linux kernel, the following vulnerability has been resolved: io_uring/query: cap user size passed to copy_struct_to_user io_handle_query_entry() clamps hdr.size for the inbound copy_from_user() but keeps the original user value as usize. copy_struct_to_user() uses that usize and, when it is larger than the kernel result, clear_user()s the trailing bytes. As hdr.size is a __u32, a query can request nearly 4 GiB of zeroing, including on the error path where res_size stays 0. The interface is reachable without a ring via IORING_REGISTER_QUERY. Reject sizes larger than PAGE_SIZE, as recommended for copy_struct_* interfaces.

Where it's fixed

ProductFixed inFixReleased
Linux
bpftool6.18 · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
bpftool6.18-debuginfo · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel-livepatch-6.18.51-120.162 · amzn 2023 1:1.0-0.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18 · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-debuginfo · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-debuginfo-common-aarch64 · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-debuginfo-common-x86_64 · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-devel · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-headers · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-modules-extra · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-modules-extra-common · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-tools · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-tools-debuginfo · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
kernel6.18-tools-devel · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
linux · Debian 14 7.2.6-1 DEBIAN-CVE-2026-81009 Sep 23, 2026
microvm-kernel6.18 · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
perf6.18 · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
perf6.18-debuginfo · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
python3-perf6.18 · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026
python3-perf6.18-debuginfo · amzn 2023 1:6.18.51-120.162.amzn2023 ALAS2023-2026-3187 Nov 7, 2026

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