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Fencer Vulns
high 7.1

CVE-2026-43006 json

io_uring/rsrc: reject zero-length fixed buffer import

published 2026-05-01 6 mo ago modified 2026-08-05 3 mo ago also EUVD-2026-26605

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

io_uring/rsrc: reject zero-length fixed buffer import

validate_fixed_range() admits buf_addr at the exact end of the registered region when len is zero, because the check uses strict greater-than (buf_end > imu->ubuf + imu->len). io_import_fixed() then computes offset == imu->len, which causes the bvec skip logic to advance past the last bio_vec entry and read bv_offset from out-of-bounds slab memory.

Return early from io_import_fixed() when len is zero. A zero-length import has no data to transfer and should not walk the bvec array at all.

BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0 Read of size 4 at addr ffff888002bcc254 by task poc/103 Call Trace: io_import_reg_buf+0x697/0x7f0 io_write_fixed+0xd9/0x250 __io_issue_sqe+0xad/0x710 io_issue_sqe+0x7d/0x1100 io_submit_sqes+0x86a/0x23c0 __do_sys_io_uring_enter+0xa98/0x1590 Allocated by task 103: The buggy address is located 12 bytes to the right of allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)

Patch / fix

  • Linux Linux 6.18.22, 6.19.12, 7.0
  • linux Debian 14 6.19.12-1

debian advisories DEBIAN-CVE-2026-43006

  • linux-nvidia Ubuntu 26.04 LTS 7.0.0-1006.6

ubuntu advisories UBUNTU-CVE-2026-43006

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.2 6.12.0-211.18.1.el10_2
  • rv RHEL 10.2 6.12.0-211.18.1.el10_2
  • perf RHEL 10.2 6.12.0-211.18.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.18.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.18.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.18.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.18.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.18.1.el10_2

red hat advisories RHSA-2026:21557

  • kernel AlmaLinux 10 6.12.0-211.18.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.18.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.18.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.18.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.18.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.18.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.18.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.18.1.el10_2

almalinux advisories ALSA-2026:21557

  • kernel Rocky Linux 10 6.12.0-211.18.1.el10_2

rocky linux advisories RLSA-2026:21557

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-43006 updated cvss 7.1

kernel: io_uring/rsrc: reject zero-length fixed buffer import

  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.18.1.el10_2, perf 6.12.0-211.18.1.el10_2, rtla 6.12.0-211.18.1.el10_2, python3-perf 6.12.0-211.18.1.el10_2, kernel-devel-matched 6.12.0-211.18.1.el10_2, kernel-64k-devel-matched 6.12.0-211.18.1.el10_2, +7 more Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.18.1.el10_2, kernel-64k 6.12.0-211.18.1.el10_2, kernel-core 6.12.0-211.18.1.el10_2, kernel-tools 6.12.0-211.18.1.el10_2, kernel-modules 6.12.0-211.18.1.el10_2, kernel-64k-core 6.12.0-211.18.1.el10_2, +28 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.18.1.el10_2 Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.18.1.el10_2, kernel-rt-64k 6.12.0-211.18.1.el10_2, kernel-rt-core 6.12.0-211.18.1.el10_2, kernel-rt-modules 6.12.0-211.18.1.el10_2, kernel-rt-64k-core 6.12.0-211.18.1.el10_2, kernel-rt-debug-core 6.12.0-211.18.1.el10_2, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.18.1.el10_2, kernel-rt-core 6.12.0-211.18.1.el10_2, kernel-rt-modules 6.12.0-211.18.1.el10_2, kernel-rt-debug-core 6.12.0-211.18.1.el10_2, kernel-rt-modules-core 6.12.0-211.18.1.el10_2, kernel-rt-debug-modules 6.12.0-211.18.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:21557
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.