Linux: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2026-43199 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 5efde07521309274f26727860774614cbc187242, e1407fb7c337373dfaaae2445d828b0b9ae26a29, 57957bc7f1865778ec9b1618e15515feb6df7eb4 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 0.41% 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 5efde07521309274f26727860774614cbc187242 or e1407fb7c337373dfaaae2445d828b0b9ae26a29 or 57957bc7f1865778ec9b1618e15515feb6df7eb4 or 546de94e41e92e1f7dc6213615fb7c794d05db98, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.75 or 6.18.16 or 6.19.6, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | cee137a634318bfbda18ee5af45d300153b57fa5 up to, but not including, 5efde07521309274f26727860774614cbc187242; cee137a634318bfbda18ee5af45d300153b57fa5 up to, but not including, e1407fb7c337373dfaaae2445d828b0b9ae26a29; cee137a634318bfbda18ee5af45d300153b57fa5 up to, but not including, 57957bc7f1865778ec9b1618e15515feb6df7eb4; cee137a634318bfbda18ee5af45d300153b57fa5 up to, but not including, 546de94e41e92e1f7dc6213615fb7c794d05db98; cee137a634318bfbda18ee5af45d300153b57fa5 up to, but not including, 859380694f434597407632c29f30fdb5e763e6cc; 6.2 | 5efde07521309274f26727860774614cbc187242, e1407fb7c337373dfaaae2445d828b0b9ae26a29, 57957bc7f1865778ec9b1618e15515feb6df7eb4, 546de94e41e92e1f7dc6213615fb7c794d05db98, 859380694f434597407632c29f30fdb5e763e6cc |
| Linux | Linux Kernel | 6.2 up to, but not including, 6.12.75; 6.13 up to, but not including, 6.18.16; 6.19 up to, but not including, 6.19.6; 7.0 | 6.12.75, 6.18.16, 6.19.6 |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix "scheduling while atomic" in IPsec MAC address query Fix a "scheduling while atomic" bug in mlx5e_ipsec_init_macs() by replacing mlx5_query_mac_address() with ether_addr_copy() to get the local MAC address directly from netdev->dev_addr. The issue occurs because mlx5_query_mac_address() queries the hardware which involves mlx5_cmd_exec() that can sleep, but it is called from the mlx5e_ipsec_handle_event workqueue which runs in atomic context. The MAC address is already available in netdev->dev_addr, so no need to query hardware. This avoids the sleeping call and resolves the bug. Call trace: BUG: scheduling while atomic: kworker/u112:2/69344/0x00000200 __schedule+0x7ab/0xa20 schedule+0x1c/0xb0 schedule_timeout+0x6e/0xf0 __wait_for_common+0x91/0x1b0 cmd_exec+0xa85/0xff0 [mlx5_core] mlx5_cmd_exec+0x1f/0x50 [mlx5_core] mlx5_query_nic_vport_mac_address+0x7b/0xd0 [mlx5_core] mlx5_query_mac_address+0x19/0x30 [mlx5_core] mlx5e_ipsec_init_macs+0xc1/0x720 [mlx5_core] mlx5e_ipsec_build_accel_xfrm_attrs+0x422/0x670 [mlx5_core] mlx5e_ipsec_handle_event+0x2b9/0x460 [mlx5_core] process_one_work+0x178/0x2e0 worker_thread+0x2ea/0x430
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
How developers prevent this class of flaw
- In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
- Use thread-safe capabilities such as the data access abstraction in Spring.
- Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
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