Cloudanix VulnDB

CVE-2023-54283

None

CVSS

—

EPSS

0.2%

Published

Dec 30, 2025

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A Linux kernel bug that could cause instability when many programs update certain maps at the same time was fixed by improving how the kernel safely reads and writes a small internal value.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Theoretical
Impact
Other
Component
OS kernel
Class
Race Condition
Remediation
Patch
Effort
Medium
Patch risk
Low

What it actually does

Data race on node->ref field in bpf_lru_list.c during concurrent LRU rotation and reference updates in percpu hash map operations, resolved by switching to READ_ONCE/WRITE_ONCE accessors.

Why it matters to the business

Kernel instability or unexpected behavior possible on systems running concurrent BPF map updates; low practical risk given the nature of the race but still requires patching to maintain stability in high-throughput environments.

How an attack unfolds

An attacker with local access triggers concurrent bpf map update batch operations that race on LRU node reference bits; the original code used data_race() which KCSAN flagged, though the fix ensures proper ordered access without changing observable behavior.

How to fix it

Upgrade the Linux kernel to a version containing commit 6eaef1b1d8720053eb1b6e7a3ff8b2ff0716bb90 or later; rebuild and reboot with the patched kernel.

How to confirm the fix worked

Confirm the running kernel contains commit 6eaef1b1d8720053eb1b6e7a3ff8b2ff0716bb90; re-run KCSAN or syzkaller tests targeting bpf_lru_list and hashtab paths to verify absence of the reported race.

Typical attack path

  1. Obtain local unprivileged access to a Linux system
  2. Load or attach BPF programs that perform frequent percpu hash map updates via batch syscalls
  3. Trigger concurrent execution paths through __bpf_lru_list_rotate and bpf_lru_node_set_ref
  4. Observe or induce kernel state inconsistency from the unsynchronized ref field access

How to detect it

Review kernel logs for KCSAN reports mentioning bpf_lru_list or __htab_lru_percpu_map_update_elem; examine audit logs for unusual volumes of bpf map update batch syscalls from untrusted processes.

What your security team should do

  • Prioritize kernel upgrade on systems with heavy BPF usage within the next maintenance window
  • Monitor for new stable kernel releases containing the fix
  • Restrict unprivileged BPF loading via sysctl until patched where feasible

The record

In the Linux kernel, the following vulnerability has been resolved: bpf: Address KCSAN report on bpf_lru_list KCSAN reported a data-race when accessing node->ref. Although node->ref does not have to be accurate, take this chance to use a more common READ_ONCE() and WRITE_ONCE() pattern instead of data_race(). There is an existing bpf_lru_node_is_ref() and bpf_lru_node_set_ref(). This patch also adds bpf_lru_node_clear_ref() to do the WRITE_ONCE(node->ref, 0) also. ================================================================== BUG: KCSAN: data-race in __bpf_lru_list_rotate / __htab_lru_percpu_map_update_elem write to 0xffff888137038deb of 1 bytes by task 11240 on cpu 1: __bpf_lru_node_move kernel/bpf/bpf_lru_list.c:113 [inline] __bpf_lru_list_rotate_active kernel/bpf/bpf_lru_list.c:149 [inline] __bpf_lru_list_rotate+0x1bf/0x750 kernel/bpf/bpf_lru_list.c:240 bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:329 [inline] bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline] bpf_lru_pop_free+0x638/0xe20 kernel/bpf/bpf_lru_list.c:499 prealloc_lru_pop kernel/bpf/hashtab.c:290 [inline] __htab_lru_percpu_map_update_elem+0xe7/0x820 kernel/bpf/hashtab.c:1316 bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313 bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200 generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687 bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534 __sys_bpf+0x338/0x810 __do_sys_bpf kernel/bpf/syscall.c:5096 [inline] __se_sys_bpf kernel/bpf/syscall.c:5094 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff888137038deb of 1 bytes by task 11241 on cpu 0: bpf_lru_node_set_ref kernel/bpf/bpf_lru_list.h:70 [inline] __htab_lru_percpu_map_update_elem+0x2f1/0x820 kernel/bpf/hashtab.c:1332 bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313 bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200 generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687 bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534 __sys_bpf+0x338/0x810 __do_sys_bpf kernel/bpf/syscall.c:5096 [inline] __se_sys_bpf kernel/bpf/syscall.c:5094 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x01 -> 0x00 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 11241 Comm: syz-executor.3 Not tainted 6.3.0-rc7-syzkaller-00136-g6a66fdd29ea1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 ==================================================================

Affected packages

Ecosystem Package Introduced Fixed
Linux Kernel 0 4.14.322
Linux Kernel 4.10.0 4.14.322
SUSE:Linux Enterprise High Availability Extension 15 SP6 kernel-default 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-default 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_19 0 1-150600.13.3.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-64kb 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-default 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-default-base 0 6.4.0-150600.23.84.1.150600.12.38.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-docs 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-obs-build 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-source 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-syms 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server 15 SP6-LTSS kernel-zfcpdump 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP6 kernel-default 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP6 kernel-default-base 0 6.4.0-150600.23.84.1.150600.12.38.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP6 kernel-docs 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP6 kernel-obs-build 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP6 kernel-source 0 6.4.0-150600.23.84.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP6 kernel-syms 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 dtb-aarch64 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-64kb 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-debug 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-default 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-default-base 0 6.4.0-150600.23.84.1.150600.12.38.1
openSUSE:Leap 15.6 kernel-docs 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-kvmsmall 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-obs-build 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-obs-qa 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-source 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-syms 0 6.4.0-150600.23.84.1
openSUSE:Leap 15.6 kernel-zfcpdump 0 6.4.0-150600.23.84.1

Related vulnerabilities