Linux: Use After Free
CVE-2025-71162 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 5f8d1d66a952d0396671e1f21ff8127a4d14fb4e, 76992310f80776b4d1f7f8915f59b92883a3e44c, ae3eed72de682ddbba507ed2d6b848c21a6b721e 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 0.21% 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 5f8d1d66a952d0396671e1f21ff8127a4d14fb4e or 76992310f80776b4d1f7f8915f59b92883a3e44c or ae3eed72de682ddbba507ed2d6b848c21a6b721e or 59cb421b0902fbef2b9512ae8ba198a20f26b41f, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.249 or 5.15.199 or 6.1.162 or 6.6.122, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f46b195799b5cb05338e7c44cb3617eacb56d755 up to, but not including, 5f8d1d66a952d0396671e1f21ff8127a4d14fb4e; f46b195799b5cb05338e7c44cb3617eacb56d755 up to, but not including, 76992310f80776b4d1f7f8915f59b92883a3e44c; f46b195799b5cb05338e7c44cb3617eacb56d755 up to, but not including, ae3eed72de682ddbba507ed2d6b848c21a6b721e; f46b195799b5cb05338e7c44cb3617eacb56d755 up to, but not including, 59cb421b0902fbef2b9512ae8ba198a20f26b41f; f46b195799b5cb05338e7c44cb3617eacb56d755 up to, but not including, cb2c9c4bb1322cc3c9984ad17db8cdd2663879ca; f46b195799b5cb05338e7c44cb3617eacb56d755 up to, but not including, be655c3736b3546f39bc8116ffbf2a3b6cac96c4; f46b195799b5cb05338e7c44cb3617eacb56d755 up to, but not including, 2efd07a7c36949e6fa36a69183df24d368bf9e96; 4.7 | 5f8d1d66a952d0396671e1f21ff8127a4d14fb4e, 76992310f80776b4d1f7f8915f59b92883a3e44c, ae3eed72de682ddbba507ed2d6b848c21a6b721e, 59cb421b0902fbef2b9512ae8ba198a20f26b41f, cb2c9c4bb1322cc3c9984ad17db8cdd2663879ca, be655c3736b3546f39bc8116ffbf2a3b6cac96c4 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 4.7 up to, but not including, 5.10.249; 5.11 up to, but not including, 5.15.199; 5.16 up to, but not including, 6.1.162; 6.2 up to, but not including, 6.6.122; 6.7 up to, but not including, 6.12.67; 6.13 up to, but not including, 6.18.7; 6.19 | 5.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.67, 6.18.7 |
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: dmaengine: tegra-adma: Fix use-after-free A use-after-free bug exists in the Tegra ADMA driver when audio streams are terminated, particularly during XRUN conditions. The issue occurs when the DMA buffer is freed by tegra_adma_terminate_all() before the vchan completion tasklet finishes accessing it. The race condition follows this sequence: 1. DMA transfer completes, triggering an interrupt that schedules the completion tasklet (tasklet has not executed yet) 2. Audio playback stops, calling tegra_adma_terminate_all() which frees the DMA buffer memory via kfree() 3. The scheduled tasklet finally executes, calling vchan_complete() which attempts to access the already-freed memory Since tasklets can execute at any time after being scheduled, there is no guarantee that the buffer will remain valid when vchan_complete() runs. Fix this by properly synchronizing the virtual channel completion: - Calling vchan_terminate_vdesc() in tegra_adma_stop() to mark the descriptors as terminated instead of freeing the descriptor. - Add the callback tegra_adma_synchronize() that calls vchan_synchronize() which kills any pending tasklets and frees any terminated descriptors. Crash logs: [ 337.427523] BUG: KASAN: use-after-free in vchan_complete+0x124/0x3b0 [ 337.427544] Read of size 8 at addr ffff000132055428 by task swapper/0/0 [ 337.427562] Call trace: [ 337.427564] dump_backtrace+0x0/0x320 [ 337.427571] show_stack+0x20/0x30 [ 337.427575] dump_stack_lvl+0x68/0x84 [ 337.427584] print_address_description.constprop.0+0x74/0x2b8 [ 337.427590] kasan_report+0x1f4/0x210 [ 337.427598] __asan_load8+0xa0/0xd0 [ 337.427603] vchan_complete+0x124/0x3b0 [ 337.427609] tasklet_action_common.constprop.0+0x190/0x1d0 [ 337.427617] tasklet_action+0x30/0x40 [ 337.427623] __do_softirq+0x1a0/0x5c4 [ 337.427628] irq_exit+0x110/0x140 [ 337.427633] handle_domain_irq+0xa4/0xe0 [ 337.427640] gic_handle_irq+0x64/0x160 [ 337.427644] call_on_irq_stack+0x20/0x4c [ 337.427649] do_interrupt_handler+0x7c/0x90 [ 337.427654] el1_interrupt+0x30/0x80 [ 337.427659] el1h_64_irq_handler+0x18/0x30 [ 337.427663] el1h_64_irq+0x7c/0x80 [ 337.427667] cpuidle_enter_state+0xe4/0x540 [ 337.427674] cpuidle_enter+0x54/0x80 [ 337.427679] do_idle+0x2e0/0x380 [ 337.427685] cpu_startup_entry+0x2c/0x70 [ 337.427690] rest_init+0x114/0x130 [ 337.427695] arch_call_rest_init+0x18/0x24 [ 337.427702] start_kernel+0x380/0x3b4 [ 337.427706] __primary_switched+0xc0/0xc8
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/2efd07a7c36949e6fa36a69183df24d368bf9e96
- git.kernel.org/stable/c/59cb421b0902fbef2b9512ae8ba198a20f26b41f
- git.kernel.org/stable/c/5f8d1d66a952d0396671e1f21ff8127a4d14fb4e
- git.kernel.org/stable/c/76992310f80776b4d1f7f8915f59b92883a3e44c
- git.kernel.org/stable/c/ae3eed72de682ddbba507ed2d6b848c21a6b721e
- git.kernel.org/stable/c/be655c3736b3546f39bc8116ffbf2a3b6cac96c4
- git.kernel.org/stable/c/cb2c9c4bb1322cc3c9984ad17db8cdd2663879ca
Other references
Recent Use After Free vulnerabilities
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- 9.8 Critical severity
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