Linux: Use After Free
CVE-2025-38109 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 5953ae44dfe5dbad374318875be834c3b7b71ee6, da15ca0553325acf68039015f2f4db750c8e2b96, 24db585d369f949f698e03d7d8017e5ae19d0497 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 5953ae44dfe5dbad374318875be834c3b7b71ee6 or da15ca0553325acf68039015f2f4db750c8e2b96 or 24db585d369f949f698e03d7d8017e5ae19d0497 or 687560d8a9a2d654829ad0da1ec24242f1de711d, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.94 or 6.12.34 or 6.15.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a7719b29a82199b90ebbf355d3332e0fbfbf6045 up to, but not including, 5953ae44dfe5dbad374318875be834c3b7b71ee6; a7719b29a82199b90ebbf355d3332e0fbfbf6045 up to, but not including, da15ca0553325acf68039015f2f4db750c8e2b96; a7719b29a82199b90ebbf355d3332e0fbfbf6045 up to, but not including, 24db585d369f949f698e03d7d8017e5ae19d0497; a7719b29a82199b90ebbf355d3332e0fbfbf6045 up to, but not including, 687560d8a9a2d654829ad0da1ec24242f1de711d; 6.5 | 5953ae44dfe5dbad374318875be834c3b7b71ee6, da15ca0553325acf68039015f2f4db750c8e2b96, 24db585d369f949f698e03d7d8017e5ae19d0497, 687560d8a9a2d654829ad0da1ec24242f1de711d |
| Linux | Linux Kernel | 6.5 up to, but not including, 6.6.94; 6.7 up to, but not including, 6.12.34; 6.13 up to, but not including, 6.15.3; 6.16 | 6.6.94, 6.12.34, 6.15.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix ECVF vports unload on shutdown flow Fix shutdown flow UAF when a virtual function is created on the embedded chip (ECVF) of a BlueField device. In such case the vport acl ingress table is not properly destroyed. ECVF functionality is independent of ecpf_vport_exists capability and thus functions mlx5_eswitch_(enable|disable)_pf_vf_vports() should not test it when enabling/disabling ECVF vports. kernel log: [] refcount_t: underflow; use-after-free. [] WARNING: CPU: 3 PID: 1 at lib/refcount.c:28 refcount_warn_saturate+0x124/0x220 ---------------- [] Call trace: [] refcount_warn_saturate+0x124/0x220 [] tree_put_node+0x164/0x1e0 [mlx5_core] [] mlx5_destroy_flow_table+0x98/0x2c0 [mlx5_core] [] esw_acl_ingress_table_destroy+0x28/0x40 [mlx5_core] [] esw_acl_ingress_lgcy_cleanup+0x80/0xf4 [mlx5_core] [] esw_legacy_vport_acl_cleanup+0x44/0x60 [mlx5_core] [] esw_vport_cleanup+0x64/0x90 [mlx5_core] [] mlx5_esw_vport_disable+0xc0/0x1d0 [mlx5_core] [] mlx5_eswitch_unload_ec_vf_vports+0xcc/0x150 [mlx5_core] [] mlx5_eswitch_disable_sriov+0x198/0x2a0 [mlx5_core] [] mlx5_device_disable_sriov+0xb8/0x1e0 [mlx5_core] [] mlx5_sriov_detach+0x40/0x50 [mlx5_core] [] mlx5_unload+0x40/0xc4 [mlx5_core] [] mlx5_unload_one_devl_locked+0x6c/0xe4 [mlx5_core] [] mlx5_unload_one+0x3c/0x60 [mlx5_core] [] shutdown+0x7c/0xa4 [mlx5_core] [] pci_device_shutdown+0x3c/0xa0 [] device_shutdown+0x170/0x340 [] __do_sys_reboot+0x1f4/0x2a0 [] __arm64_sys_reboot+0x2c/0x40 [] invoke_syscall+0x78/0x100 [] el0_svc_common.constprop.0+0x54/0x184 [] do_el0_svc+0x30/0xac [] el0_svc+0x48/0x160 [] el0t_64_sync_handler+0xa4/0x12c [] el0t_64_sync+0x1a4/0x1a8 [] --[ end trace 9c4601d68c70030e ]---
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.