CVE-2025-39979net/mlx5: fs, fix UAF in flow counter release
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In the Linux kernel, the following vulnerability has been resolved: net/mlx5: fs, fix UAF in flow counter release Fix a kernel trace [1] caused by releasing an HWS action of a local flow counter in mlx5_cmd_hws_delete_fte(), where the HWS action refcount and mutex were not initialized and the counter struct could already be freed when deleting the rule. Fix it by adding the missing initializations and adding refcount for the local flow counter struct. [1] Kernel log: Call Trace: <TASK> dump_stack_lvl+0x34/0x48 mlx5_fs_put_hws_action.part.0.cold+0x21/0x94 [mlx5_core] mlx5_fc_put_hws_action+0x96/0xad [mlx5_core] mlx5_fs_destroy_fs_actions+0x8b/0x152 [mlx5_core] mlx5_cmd_hws_delete_fte+0x5a/0xa0 [mlx5_core] del_hw_fte+0x1ce/0x260 [mlx5_core] mlx5_del_flow_rules+0x12d/0x240 [mlx5_core] ? ttwu_queue_wakelist+0xf4/0x110 mlx5_ib_destroy_flow+0x103/0x1b0 [mlx5_ib] uverbs_free_flow+0x20/0x50 [ib_uverbs] destroy_hw_idr_uobject+0x1b/0x50 [ib_uverbs] uverbs_destroy_uobject+0x34/0x1a0 [ib_uverbs] uobj_destroy+0x3c/0x80 [ib_uverbs] ib_uverbs_run_method+0x23e/0x360 [ib_uverbs] ? uverbs_finalize_object+0x60/0x60 [ib_uverbs] ib_uverbs_cmd_verbs+0x14f/0x2c0 [ib_uverbs] ? do_tty_write+0x1a9/0x270 ? file_tty_write.constprop.0+0x98/0xc0 ? new_sync_write+0xfc/0x190 ib_uverbs_ioctl+0xd7/0x160 [ib_uverbs] __x64_sys_ioctl+0x87/0xc0 do_syscall_64+0x59/0x90
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Deferred
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.