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Linux KernelOperating system · Linux

CVE-2023-53577

HIGH · 7.8 CVSS v3.1 Published 2025-10-04
Fix available
A fix is available. Upgrade to 5.15.126 / 6.1.45 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: bpf, cpumap: Make sure kthread is running before map update returns The following warning was reported when running stress-mode enabled xdp_redirect_cpu with some RT threads: ------------[ cut here ]------------ WARNING: CPU: 4 PID: 65 at kernel/bpf/cpumap.c:135 CPU: 4 PID: 65 Comm: kworker/4:1 Not tainted 6.5.0-rc2+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Workqueue: events cpu_map_kthread_stop RIP: 0010:put_cpu_map_entry+0xda/0x220 ...... Call Trace: <TASK> ? show_regs+0x65/0x70 ? __warn+0xa5/0x240 ...... ? put_cpu_map_entry+0xda/0x220 cpu_map_kthread_stop+0x41/0x60 process_one_work+0x6b0/0xb80 worker_thread+0x96/0x720 kthread+0x1a5/0x1f0 ret_from_fork+0x3a/0x70 ret_from_fork_asm+0x1b/0x30 </TASK> The root cause is the same as commit 436901649731 ("bpf: cpumap: Fix memory leak in cpu_map_update_elem"). The kthread is stopped prematurely by kthread_stop() in cpu_map_kthread_stop(), and kthread() doesn't call cpu_map_kthread_run() at all but XDP program has already queued some frames or skbs into ptr_ring. So when __cpu_map_ring_cleanup() checks the ptr_ring, it will find it was not emptied and report a warning. An alternative fix is to use __cpu_map_ring_cleanup() to drop these pending frames or skbs when kthread_stop() returns -EINTR, but it may confuse the user, because these frames or skbs have been handled correctly by XDP program. So instead of dropping these frames or skbs, just make sure the per-cpu kthread is running before __cpu_map_entry_alloc() returns. After apply the fix, the error handle for kthread_stop() will be unnecessary because it will always return 0, so just remove it.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-401

Allocated memory is never released on some path, so a long-running service or a repeatedly triggered request steadily consumes memory until performance degrades or the process crashes. Attackers exploit it by simply driving the leaking path. Remediation is pairing every allocation with a release and using ownership patterns or tooling to catch what leaks.

General guidance for the memory leak class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.15, < 5.15.126>= 5.16, < 6.1.45>= 6.2, < 6.4.10= 6.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.15.126 / 6.1.45 / 6.4.10 or later
Fixed in 5.15.1266.1.456.4.10
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel version 5.15.126 or later (5.15.x series), 6.1.45 or later (6.1.x series), 6.4.10 or later (6.4.x series), or 6.5.1 or later (6.5.x series). For best long-term support, consider upgrading to the latest stable 6.6.x or 6.7.x kernel if available.

  1. Identify the currently running Linux kernel version using 'uname -r'
  2. Check if the current version falls within any of the affected ranges: 4.15 to 5.15.125, 5.16 to 6.1.44, 6.2 to 6.4.9, or exactly 6.5
  3. If affected, schedule a maintenance window for the kernel upgrade
  4. Update the system package repository and upgrade the Linux kernel to a fixed version
  5. For RHEL/CentOS systems: run 'yum update kernel' or 'dnf update kernel'
  6. For Debian/Ubuntu systems: run 'apt-get update && apt-get install linux-image-generic' (or equivalent kernel package)
  7. Reboot the system to load the new kernel using 'reboot'
  8. After reboot, verify the new kernel version with 'uname -r' and confirm it is >= 5.15.126, >= 6.1.45, >= 6.4.10, or >= 6.5.1
Caveat Kernel upgrades may require rebooting services; verify application compatibility with newer kernel versions in a staging environment before production deployment.

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-53577 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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