Summary
In the Linux kernel, the following vulnerability has been resolved: mm: kmem: fix a NULL pointer...
In the Linux kernel, the following vulnerability has been resolved:
mm: kmem: fix a NULL pointer dereference in obj_stock_flush_required()
KCSAN found an issue in obj_stock_flush_required():
stock->cached_objcg can be reset between the check and dereference:
==================================================================
BUG: KCSAN: data-race in drain_all_stock / drain_obj_stock
write to 0xffff888237c2a2f8 of 8 bytes by task 19625 on cpu 0:
drain_obj_stock+0x408/0x4e0 mm/memcontrol.c:3306
refill_obj_stock+0x9c/0x1e0 mm/memcontrol.c:3340
obj_cgroup_uncharge+0xe/0x10 mm/memcontrol.c:3408
memcg_slab_free_hook mm/slab.h:587 [inline]
__cache_free mm/slab.c:3373 [inline]
__do_kmem_cache_free mm/slab.c:3577 [inline]
kmem_cache_free+0x105/0x280 mm/slab.c:3602
__d_free fs/dcache.c:298 [inline]
dentry_free fs/dcache.c:375 [inline]
__dentry_kill+0x422/0x4a0 fs/dcache.c:621
dentry_kill+0x8d/0x1e0
dput+0x118/0x1f0 fs/dcache.c:913
__fput+0x3bf/0x570 fs/file_table.c:329
____fput+0x15/0x20 fs/file_table.c:349
task_work_run+0x123/0x160 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xcf/0xe0 kernel/entry/common.c:171
exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:203
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
read to 0xffff888237c2a2f8 of 8 bytes by task 19632 on cpu 1:
obj_stock_flush_required mm/memcontrol.c:3319 [inline]
drain_all_stock+0x174/0x2a0 mm/memcontrol.c:2361
try_charge_memcg+0x6d0/0xd10 mm/memcontrol.c:2703
try_charge mm/memcontrol.c:2837 [inline]
mem_cgroup_charge_skmem+0x51/0x140 mm/memcontrol.c:7290
sock_reserve_memory+0xb1/0x390 net/core/sock.c:1025
sk_setsockopt+0x800/0x1e70 net/core/sock.c:1525
udp_lib_setsockopt+0x99/0x6c0 net/ipv4/udp.c:2692
udp_setsockopt+0x73/0xa0 net/ipv4/udp.c:2817
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3668
__sys_setsockopt+0x1c3/0x230 net/socket.c:2271
__do_sys_setsockopt net/socket.c:2282 [inline]
__se_sys_setsockopt net/socket.c:2279 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2279
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: 0xffff8881382d52c0 -> 0xffff888138893740
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19632 Comm: syz-executor.0 Not tainted 6.3.0-rc2-syzkaller-00387-g534293368afa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Fix it by using READ_ONCE()/WRITE_ONCE() for all accesses to
stock->cached_objcg.
Impact
The application dereferences a null pointer, causing a crash. Typical impact: denial of service via crash.
CVE-2023-53401 has a CVSS score of 4.7 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2023-53401? CVE-2023-53401 is a medium-severity null pointer dereference vulnerability. No fixed version is listed yet. The application dereferences a null pointer, causing a crash.
- How severe is CVE-2023-53401? CVE-2023-53401 has a CVSS score of 4.7 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2023-53401? No fixed version is listed for CVE-2023-53401 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2023-53401 exploitable, and should I be worried? Whether CVE-2023-53401 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-53401 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.