What is CVE-2023-53557?

CVE-2023-53557 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 5.18 onward and patched in 6.1.40, 6.4.5 and 6.5. CVE-2023-53557 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2023-53557?

CVE-2023-53557 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-2023-53557?

Yes, CVE-2023-53557 has been patched. Fixed versions include 6.1.40, 6.4.5 and 6.5. If you are running Linux kernel 5.18 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2023-53557 actively exploited?

CVE-2023-53557 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2023-53557

Medium

In the Linux kernel, the following vulnerability has been resolved: fprobe: Release rethook after the ftrace_ops is unregistered While running bpf selftests it's possible to get following fault: general protection fault, probably for non-canonical address \ 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI ... Call Trace: <TASK> fprobe_handler+0xc1/0x270 ? __pfx_bpf_testmod_init+0x10/0x10 ? __pfx_bpf_testmod_init+0x10/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_testmod_init+0x22/0x80 ? do_one_initcall+0x63/0x2e0 ? rcu_is_watching+0xd/0x40 ? kmalloc_trace+0xaf/0xc0 ? do_init_module+0x60/0x250 ? __do_sys_finit_module+0xac/0x120 ? do_syscall_64+0x37/0x90 ? entry_SYSCALL_64_after_hwframe+0x72/0xdc </TASK> In unregister_fprobe function we can't release fp->rethook while it's possible there are some of its users still running on another cpu. Moving rethook_free call after fp->ops is unregistered with unregister_ftrace_function call.

Package Linux Kernel

Published 2025-10-04

Last modified 2026-03-21

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 5.18 and later are affected. Fixed in 6.1.40, 6.4.5, 6.5 and their respective stable series.

Affected from

≥ 5.18

Fixed in

✓ 6.1.40 6.1.x ✓ 6.4.5 6.4.x ✓ 6.5

References

The following references provide additional information about CVE-2023-53557 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/03d63255a5783243c110aec5e6ae2f1475c3be76
Patch
Kernel patch commit
https://git.kernel.org/stable/c/5f81018753dfd4989e33ece1f0cb6b8aae498b82
Patch
Kernel patch commit
https://git.kernel.org/stable/c/ce3ec57faff559ccae1e0150c1f077eb2df648a4
Patch

Details

CVE ID CVE-2023-53557

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-10-04

Modified 2026-03-21

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2023-53557?

CVE-2023-53557 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 5.18 onward and has been patched in 6.1.40, 6.4.5 and 6.5. CVE-2023-53557 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2023-53557?

CVE-2023-53557 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-2023-53557?

Yes — CVE-2023-53557 has been patched. Fixed versions include 6.1.40, 6.4.5 and 6.5. If you are running Linux kernel 5.18 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2023-53557 actively exploited?

No — CVE-2023-53557 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.