Linux: Use After Free
CVE-2025-38464 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 03dcdd2558e1e55bf843822fe4363dcb48743f2b, 15a6f4971e2f157d57e09ea748d1fbc714277aa4, dab8ded2e5ff41012a6ff400b44dbe76ccf3592a 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 0.22% 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 03dcdd2558e1e55bf843822fe4363dcb48743f2b or 15a6f4971e2f157d57e09ea748d1fbc714277aa4 or dab8ded2e5ff41012a6ff400b44dbe76ccf3592a or 1dbf7cd2454a28b1da700085b99346b5445aeabb, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.296 or 5.10.240 or 5.15.189 or 6.1.146, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, 03dcdd2558e1e55bf843822fe4363dcb48743f2b; c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, 15a6f4971e2f157d57e09ea748d1fbc714277aa4; c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, dab8ded2e5ff41012a6ff400b44dbe76ccf3592a; c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, 1dbf7cd2454a28b1da700085b99346b5445aeabb; c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, be4b8392da7978294f2f368799d29dd509fb6c4d; c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, 50aa2d121bc2cfe2d825f8a331ea75dfaaab6a50; c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, 3b89e17b2fd64012682bed158d9eb3d2e96dec42; c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f up to, but not including, 667eeab4999e981c96b447a4df5f20bdf5c26f13; and 1 more ranges | 03dcdd2558e1e55bf843822fe4363dcb48743f2b, 15a6f4971e2f157d57e09ea748d1fbc714277aa4, dab8ded2e5ff41012a6ff400b44dbe76ccf3592a, 1dbf7cd2454a28b1da700085b99346b5445aeabb, be4b8392da7978294f2f368799d29dd509fb6c4d, 50aa2d121bc2cfe2d825f8a331ea75dfaaab6a50 |
| Linux | Linux Kernel | 3.11 up to, but not including, 5.4.296; 5.5 up to, but not including, 5.10.240; 5.11 up to, but not including, 5.15.189; 5.16 up to, but not including, 6.1.146; 6.2 up to, but not including, 6.6.99; 6.7 up to, but not including, 6.12.39; 6.13 up to, but not including, 6.15.7; 6.16 | 5.4.296, 5.10.240, 5.15.189, 6.1.146, 6.6.99, 6.12.39 |
| Debian | Debian Linux | 11.0 | Not stated |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: tipc: Fix use-after-free in tipc_conn_close(). syzbot reported a null-ptr-deref in tipc_conn_close() during netns dismantle. [0] tipc_topsrv_stop() iterates tipc_net(net)->topsrv->conn_idr and calls tipc_conn_close() for each tipc_conn. The problem is that tipc_conn_close() is called after releasing the IDR lock. At the same time, there might be tipc_conn_recv_work() running and it could call tipc_conn_close() for the same tipc_conn and release its last ->kref. Once we release the IDR lock in tipc_topsrv_stop(), there is no guarantee that the tipc_conn is alive. Let's hold the ref before releasing the lock and put the ref after tipc_conn_close() in tipc_topsrv_stop(). [0]: BUG: KASAN: use-after-free in tipc_conn_close+0x122/0x140 net/tipc/topsrv.c:165 Read of size 8 at addr ffff888099305a08 by task kworker/u4:3/435 CPU: 0 PID: 435 Comm: kworker/u4:3 Not tainted 4.19.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433 tipc_conn_close+0x122/0x140 net/tipc/topsrv.c:165 tipc_topsrv_stop net/tipc/topsrv.c:701 [inline] tipc_topsrv_exit_net+0x27b/0x5c0 net/tipc/topsrv.c:722 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:553 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Allocated by task 23: kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] tipc_conn_alloc+0x43/0x4f0 net/tipc/topsrv.c:192 tipc_topsrv_accept+0x1b5/0x280 net/tipc/topsrv.c:470 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Freed by task 23: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 tipc_conn_kref_release net/tipc/topsrv.c:150 [inline] kref_put include/linux/kref.h:70 [inline] conn_put+0x2cd/0x3a0 net/tipc/topsrv.c:155 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 The buggy address belongs to the object at ffff888099305a00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 8 bytes inside of 512-byte region [ffff888099305a00, ffff888099305c00) The buggy address belongs to the page: page:ffffea000264c140 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffffea00028b6b88 ffffea0002cd2b08 ffff88813bff0940 raw: 0000000000000000 ffff888099305000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888099305900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888099305980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888099305a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888099305a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888099305b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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
- git.kernel.org/stable/c/03dcdd2558e1e55bf843822fe4363dcb48743f2b
- git.kernel.org/stable/c/15a6f4971e2f157d57e09ea748d1fbc714277aa4
- git.kernel.org/stable/c/1dbf7cd2454a28b1da700085b99346b5445aeabb
- git.kernel.org/stable/c/3b89e17b2fd64012682bed158d9eb3d2e96dec42
- git.kernel.org/stable/c/50aa2d121bc2cfe2d825f8a331ea75dfaaab6a50
- git.kernel.org/stable/c/667eeab4999e981c96b447a4df5f20bdf5c26f13
- git.kernel.org/stable/c/be4b8392da7978294f2f368799d29dd509fb6c4d
- git.kernel.org/stable/c/dab8ded2e5ff41012a6ff400b44dbe76ccf3592a
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlThird Party Advisory
- lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlThird Party Advisory
Recent Use After Free vulnerabilities
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- 9.8 Critical severity
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