CVE-2025-39881 (CNNVD-202509-3719)
中文标题:
Linux kernel 安全漏洞
英文标题:
kernfs: Fix UAF in polling when open file is released
漏洞描述
中文描述:
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于PSI监控机制中存在释放后重用问题，可能导致内存损坏。
英文描述:
In the Linux kernel, the following vulnerability has been resolved: kernfs: Fix UAF in polling when open file is released A use-after-free (UAF) vulnerability was identified in the PSI (Pressure Stall Information) monitoring mechanism: BUG: KASAN: slab-use-after-free in psi_trigger_poll+0x3c/0x140 Read of size 8 at addr ffff3de3d50bd308 by task systemd/1 psi_trigger_poll+0x3c/0x140 cgroup_pressure_poll+0x70/0xa0 cgroup_file_poll+0x8c/0x100 kernfs_fop_poll+0x11c/0x1c0 ep_item_poll.isra.0+0x188/0x2c0 Allocated by task 1: cgroup_file_open+0x88/0x388 kernfs_fop_open+0x73c/0xaf0 do_dentry_open+0x5fc/0x1200 vfs_open+0xa0/0x3f0 do_open+0x7e8/0xd08 path_openat+0x2fc/0x6b0 do_filp_open+0x174/0x368 Freed by task 8462: cgroup_file_release+0x130/0x1f8 kernfs_drain_open_files+0x17c/0x440 kernfs_drain+0x2dc/0x360 kernfs_show+0x1b8/0x288 cgroup_file_show+0x150/0x268 cgroup_pressure_write+0x1dc/0x340 cgroup_file_write+0x274/0x548 Reproduction Steps: 1. Open test/cpu.pressure and establish epoll monitoring 2. Disable monitoring: echo 0 > test/cgroup.pressure 3. Re-enable monitoring: echo 1 > test/cgroup.pressure The race condition occurs because: 1. When cgroup.pressure is disabled (echo 0 > cgroup.pressure), it: - Releases PSI triggers via cgroup_file_release() - Frees of->priv through kernfs_drain_open_files() 2. While epoll still holds reference to the file and continues polling 3. Re-enabling (echo 1 > cgroup.pressure) accesses freed of->priv epolling disable/enable cgroup.pressure fd=open(cpu.pressure) while(1) ... epoll_wait kernfs_fop_poll kernfs_get_active = true echo 0 > cgroup.pressure ... cgroup_file_show kernfs_show // inactive kn kernfs_drain_open_files cft->release(of); kfree(ctx); ... kernfs_get_active = false echo 1 > cgroup.pressure kernfs_show kernfs_activate_one(kn); kernfs_fop_poll kernfs_get_active = true cgroup_file_poll psi_trigger_poll // UAF ... end: close(fd) To address this issue, introduce kernfs_get_active_of() for kernfs open files to obtain active references. This function will fail if the open file has been released. Replace kernfs_get_active() with kernfs_get_active_of() to prevent further operations on released file descriptors.
CWE类型:
标签:
受影响产品
| 厂商 | 产品 | 版本 | 版本范围 | 平台 | CPE |
|---|---|---|---|---|---|
| Linux | Linux | - | < 34d9cafd469c69ad85e6a36b4303c78382cf5c79 | - |
cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*
|
| Linux | Linux | 6.1 | - | - |
cpe:2.3:a:linux:linux:6.1:*:*:*:*:*:*:*
|
解决方案
中文解决方案:
英文解决方案:
临时解决方案:
CVSS评分详情
时间信息
利用信息
数据源详情
| 数据源 | 记录ID | 版本 | 提取时间 |
|---|---|---|---|
| CVE | cve_CVE-2025-39881 |
2025-11-11 15:23:19 | 2025-11-11 07:40:29 |
| NVD | nvd_CVE-2025-39881 |
2025-11-11 15:01:03 | 2025-11-11 07:48:18 |
| CNNVD | cnnvd_CNNVD-202509-3719 |
2025-11-11 15:12:58 | 2025-11-11 08:00:13 |
版本与语言
安全公告
变更历史
查看详细变更
- vulnerability_type: 未提取 -> 其他
- severity: SeverityLevel.MEDIUM -> SeverityLevel.UNKNOWN
- cvss_score: 未提取 -> 0.0
- cnnvd_id: 未提取 -> CNNVD-202509-3719
- data_sources: ['cve', 'nvd'] -> ['cnnvd', 'cve', 'nvd']
查看详细变更
- affected_products_count: 6 -> 2
- references_count: 5 -> 6
- data_sources: ['cve'] -> ['cve', 'nvd']