CVE-2025-21981 ice: fix memory leak in aRFS after reset
A memory leak in the Linux kernel ice driver during reset allows attackers to exhaust system memory, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-21981?
CVE-2025-21981 is a medium-severity denial of service vulnerability in Linux kernel, published on 1 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ice: fix memory leak in aRFS after reset
Fix aRFS (accelerated Receive Flow Steering) structures memory leak by adding a checker to verify if aRFS memory is already allocated while configuring VSI. aRFS objects are allocated in two cases: - as part of VSI initialization (at probe), and - as part of reset handling
However, VSI reconfiguration executed during reset involves memory allocation one more time, without prior releasing already allocated resources. This led to the memory leak with the following signature:
[root@os-delivery ~]# cat /sys/kernel/debug/kmemleak unreferenced object 0xff3c1ca7252e6000 (size 8192): comm "kworker/0:0", pid 8, jiffies 4296833052 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 0): [<ffffffff991ec485>] __kmalloc_cache_noprof+0x275/0x340 [<ffffffffc0a6e06a>] ice_init_arfs+0x3a/0xe0 [ice] [<ffffffffc09f1027>] ice_vsi_cfg_def+0x607/0x850 [ice] [<ffffffffc09f244b>] ice_vsi_setup+0x5b/0x130 [ice] [<ffffffffc09c2131>] ice_init+0x1c1/0x460 [ice] [<ffffffffc09c64af>] ice_probe+0x2af/0x520 [ice] [<ffffffff994fbcd3>] local_pci_probe+0x43/0xa0 [<ffffffff98f07103>] work_for_cpu_fn+0x13/0x20 [<ffffffff98f0b6d9>] process_one_work+0x179/0x390 [<ffffffff98f0c1e9>] worker_thread+0x239/0x340 [<ffffffff98f14abc>] kthread+0xcc/0x100 [<ffffffff98e45a6d>] ret_from_fork+0x2d/0x50 [<ffffffff98e083ba>] ret_from_fork_asm+0x1a/0x30 ...
Weakness: CWE-401
Which versions are affected by CVE-2025-21981?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21981?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-21981 being exploited?
There is no known exploitation of CVE-2025-21981 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-59757, AZL-59835, BELL-CVE-2025-21981, DEBIAN-CVE-2025-21981, GHSA-7jcj-vjq7-xp8h, ROOT-OS-UBUNTU-2404-CVE-2025-21981 and 1 more.