Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix use-after...
In the Linux kernel, the following vulnerability has been resolved:
smb: client: Fix use-after-free in cifs_fill_dirent
There is a race condition in the readdir concurrency process, which may
access the rsp buffer after it has been released, triggering the
following KASAN warning.
==================================================================
BUG: KASAN: slab-use-after-free in cifs_fill_dirent+0xb03/0xb60 [cifs]
Read of size 4 at addr ffff8880099b819c by task a.out/342975
CPU: 2 UID: 0 PID: 342975 Comm: a.out Not tainted 6.15.0-rc6+ #240 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014
Call Trace:
dump_stack_lvl+0x53/0x70
print_report+0xce/0x640
kasan_report+0xb8/0xf0
cifs_fill_dirent+0xb03/0xb60 [cifs]
cifs_readdir+0x12cb/0x3190 [cifs]
iterate_dir+0x1a1/0x520
__x64_sys_getdents+0x134/0x220
do_syscall_64+0x4b/0x110
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f996f64b9f9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89
f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
f0 ff ff 0d f7 c3 0c 00 f7 d8 64 89 8
RSP: 002b:00007f996f53de78 EFLAGS: 00000207 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f996f53ecdc RCX: 00007f996f64b9f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f996f53dea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000207 R12: ffffffffffffff88
R13: 0000000000000000 R14: 00007ffc8cd9a500 R15: 00007f996f51e000
Allocated by task 408:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
__kasan_slab_alloc+0x6e/0x70
kmem_cache_alloc_noprof+0x117/0x3d0
mempool_alloc_noprof+0xf2/0x2c0
cifs_buf_get+0x36/0x80 [cifs]
allocate_buffers+0x1d2/0x330 [cifs]
cifs_demultiplex_thread+0x22b/0x2690 [cifs]
kthread+0x394/0x720
ret_from_fork+0x34/0x70
ret_from_fork_asm+0x1a/0x30
Freed by task 342979:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x37/0x50
kmem_cache_free+0x2b8/0x500
cifs_buf_release+0x3c/0x70 [cifs]
cifs_readdir+0x1c97/0x3190 [cifs]
iterate_dir+0x1a1/0x520
__x64_sys_getdents64+0x134/0x220
do_syscall_64+0x4b/0x110
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The buggy address belongs to the object at ffff8880099b8000
which belongs to the cache cifs_request of size 16588
The buggy address is located 412 bytes inside of
freed 16588-byte region [ffff8880099b8000, ffff8880099bc0cc)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x99b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000
head: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001
head: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000266e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880099b8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880099b8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880099b8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880099b8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880099b8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
POC is available in the link [1].
The problem triggering process is as follows:
Process 1 Process 2
---truncated---
Impact
Memory is accessed after it has been freed, leading to undefined behavior in native code. Typical impact: memory corruption, crash, or potential code execution.
CVE-2025-38051 has a CVSS score of 7.0 (High). 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-2025-38051? CVE-2025-38051 is a high-severity use after free vulnerability. No fixed version is listed yet. Memory is accessed after it has been freed, leading to undefined behavior in native code.
- How severe is CVE-2025-38051? CVE-2025-38051 has a CVSS score of 7.0 (High). 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-2025-38051? No fixed version is listed for CVE-2025-38051 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-38051 exploitable, and should I be worried? Whether CVE-2025-38051 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-2025-38051 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.