What is CVE-2026-64426?

CVE-2026-64426 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.13 onward and patched in 6.18.39, 7.1.4 and 7.2. CVE-2026-64426 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64426?

CVE-2026-64426 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-64426?

Yes, CVE-2026-64426 has been patched. Fixed versions include 6.18.39, 7.1.4 and 7.2. If you are running Linux kernel 6.13 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64426 actively exploited?

CVE-2026-64426 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-64426

Medium

In the Linux kernel, the following vulnerability has been resolved: io_uring/nop: fix file reference leak with IOSQE_FIXED_FILE NOP file-acquisition support choses between a fixed (registered) file and a normal fget()'d file based on its own IORING_NOP_FIXED_FILE flag in sqe->nop_flags. However, a request's REQ_F_FIXED_FILE is set independently from the generic IOSQE_FIXED_FILE sqe flag during request init, before the issue handler runs. If a NOP is submitted with IOSQE_FIXED_FILE set (so REQ_F_FIXED_FILE is set) but without IORING_NOP_FIXED_FILE, io_nop() takes the normal path and grabs a real reference via io_file_get_normal(). On completion, io_put_file() only drops the reference when REQ_F_FIXED_FILE is clear, so the fget()'d file is never released and leaks: BUG: memory leak unreferenced object 0xffff88800f42c240 (size 176): kmem_cache_alloc_noprof+0x358/0x440 alloc_empty_file+0x57/0x180 path_openat+0x44/0x1e50 do_file_open+0x121/0x200 do_sys_openat2+0xa7/0x150 __x64_sys_openat+0x82/0xf0 Decide between fixed and normal file acquisition from REQ_F_FIXED_FILE, the same way io_assign_file() does for every other opcode, and fold IORING_NOP_FIXED_FILE into REQ_F_FIXED_FILE at prep time.

Package Linux Kernel

Published 2026-07-25

Last modified 2026-09-04

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 6.13 and later are affected. Fixed in 6.18.39, 7.1.4, 7.2 and their respective stable series.

Affected from

≥ 6.13

Fixed in

✓ 6.18.39 6.18.x ✓ 7.1.4 7.1.x ✓ 7.2

References

3 total

Kernel Git
https://git.kernel.org/stable/c/2564ca2e31bd8ee8348362941af2ee4671e487ca

Patch
Kernel Git
https://git.kernel.org/stable/c/722869fcff598fad20d5ab79c305897a7534708b

Patch
Kernel Git
https://git.kernel.org/stable/c/7267717f35787167fcce4bc14f6ef3fa06682dcf

Patch

Details

CVE ID CVE-2026-64426

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-07-25

Modified 2026-09-04

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-64426?

CVE-2026-64426 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.13 onward and has been patched in 6.18.39, 7.1.4 and 7.2. CVE-2026-64426 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64426?

CVE-2026-64426 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-64426?

Yes. CVE-2026-64426 has been patched. Fixed versions include 6.18.39, 7.1.4 and 7.2. If you are running Linux kernel 6.13 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64426 actively exploited?

No. CVE-2026-64426 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.