CVE-2025-38500
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-08-12

Last updated on: 2025-11-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: xfrm: interface: fix use-after-free after changing collect_md xfrm interface collect_md property on xfrm interfaces can only be set on device creation, thus xfrmi_changelink() should fail when called on such interfaces. The check to enforce this was done only in the case where the xi was returned from xfrmi_locate() which doesn't look for the collect_md interface, and thus the validation was never reached. Calling changelink would thus errornously place the special interface xi in the xfrmi_net->xfrmi hash, but since it also exists in the xfrmi_net->collect_md_xfrmi pointer it would lead to a double free when the net namespace was taken down [1]. Change the check to use the xi from netdev_priv which is available earlier in the function to prevent changes in xfrm collect_md interfaces. [1] resulting oops: [ 8.516540] kernel BUG at net/core/dev.c:12029! [ 8.516552] Oops: invalid opcode: 0000 [#1] SMP NOPTI [ 8.516559] CPU: 0 UID: 0 PID: 12 Comm: kworker/u80:0 Not tainted 6.15.0-virtme #5 PREEMPT(voluntary) [ 8.516565] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 8.516569] Workqueue: netns cleanup_net [ 8.516579] RIP: 0010:unregister_netdevice_many_notify+0x101/0xab0 [ 8.516590] Code: 90 0f 0b 90 48 8b b0 78 01 00 00 48 8b 90 80 01 00 00 48 89 56 08 48 89 32 4c 89 80 78 01 00 00 48 89 b8 80 01 00 00 eb ac 90 <0f> 0b 48 8b 45 00 4c 8d a0 88 fe ff ff 48 39 c5 74 5c 41 80 bc 24 [ 8.516593] RSP: 0018:ffffa93b8006bd30 EFLAGS: 00010206 [ 8.516598] RAX: ffff98fe4226e000 RBX: ffffa93b8006bd58 RCX: ffffa93b8006bc60 [ 8.516601] RDX: 0000000000000004 RSI: 0000000000000000 RDI: dead000000000122 [ 8.516603] RBP: ffffa93b8006bdd8 R08: dead000000000100 R09: ffff98fe4133c100 [ 8.516605] R10: 0000000000000000 R11: 00000000000003d2 R12: ffffa93b8006be00 [ 8.516608] R13: ffffffff96c1a510 R14: ffffffff96c1a510 R15: ffffa93b8006be00 [ 8.516615] FS: 0000000000000000(0000) GS:ffff98fee73b7000(0000) knlGS:0000000000000000 [ 8.516619] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 8.516622] CR2: 00007fcd2abd0700 CR3: 000000003aa40000 CR4: 0000000000752ef0 [ 8.516625] PKRU: 55555554 [ 8.516627] Call Trace: [ 8.516632] <TASK> [ 8.516635] ? rtnl_is_locked+0x15/0x20 [ 8.516641] ? unregister_netdevice_queue+0x29/0xf0 [ 8.516650] ops_undo_list+0x1f2/0x220 [ 8.516659] cleanup_net+0x1ad/0x2e0 [ 8.516664] process_one_work+0x160/0x380 [ 8.516673] worker_thread+0x2aa/0x3c0 [ 8.516679] ? __pfx_worker_thread+0x10/0x10 [ 8.516686] kthread+0xfb/0x200 [ 8.516690] ? __pfx_kthread+0x10/0x10 [ 8.516693] ? __pfx_kthread+0x10/0x10 [ 8.516697] ret_from_fork+0x82/0xf0 [ 8.516705] ? __pfx_kthread+0x10/0x10 [ 8.516709] ret_from_fork_asm+0x1a/0x30 [ 8.516718] </TASK>
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2025-08-12
Last Modified
2025-11-03
Generated
2026-05-07
AI Q&A
2025-08-12
EPSS Evaluated
2026-05-05
NVD
CVE-2025-38500
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.1.153-1
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-416 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.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a use-after-free bug in the Linux kernel's xfrm interface related to the collect_md property. The collect_md property can only be set when the interface is created, but the function xfrmi_changelink() did not properly enforce this restriction. As a result, the system could erroneously place a special interface in internal kernel data structures twice, leading to a double free when the network namespace is torn down. This causes a kernel crash (oops) due to invalid memory operations.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash due to a double free error when network namespaces are cleaned up. This can lead to system instability, denial of service, or potential exploitation if an attacker can trigger the bug, affecting the availability and reliability of the system.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability manifests as a kernel BUG and oops related to xfrm interfaces when the collect_md property is improperly changed. Detection can be done by monitoring kernel logs for messages similar to the provided oops output, such as 'kernel BUG at net/core/dev.c:12029!' or 'Oops: invalid opcode'. You can check kernel logs using commands like 'dmesg | grep -i "kernel BUG"' or 'journalctl -k | grep -i oops'. There are no specific commands to detect the vulnerability directly, but monitoring for these kernel errors related to xfrm interfaces is recommended.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation involves updating the Linux kernel to a version where this vulnerability is fixed, as the issue is resolved by changing the check to use the xi from netdev_priv earlier in the function to prevent changes in xfrm collect_md interfaces. Until the update is applied, avoid changing the collect_md property on existing xfrm interfaces, as it should only be set on device creation. Monitoring and preventing calls to changelink on such interfaces can reduce the risk of triggering the bug.


Ask Our AI Assistant
Need more information? Ask your question to get an AI reply (Powered by our expertise)
0/70
EPSS Chart