Linux: Use After Free
CVE-2026-46056 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions ea18732d2614557e59f4c0d8cdbe6611aeab33b7, d28311539ac9f65e29308ea219ecaa48aa5e76e5, b6ae482f88654db407c8c17619d4b62959b903ef 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 0.28% 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 ea18732d2614557e59f4c0d8cdbe6611aeab33b7 or d28311539ac9f65e29308ea219ecaa48aa5e76e5 or b6ae482f88654db407c8c17619d4b62959b903ef or 204028af77a265e31ceb4ba7f643349a3cca72b2, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.175 or 6.6.140 or 6.12.86 or 6.18.27, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, ea18732d2614557e59f4c0d8cdbe6611aeab33b7; 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, d28311539ac9f65e29308ea219ecaa48aa5e76e5; 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, b6ae482f88654db407c8c17619d4b62959b903ef; 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, 204028af77a265e31ceb4ba7f643349a3cca72b2; 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, 01a6431766c35dfedb86e0cb5d3fc80c6d604a47; 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, e08d75753db17aa943d7622f09d9c217b5bfd3b8; 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, 8c6443bb9257b780986fb67ec08565bf48ecb8d7; 92a25256f142d55e25f9959441cea6ddeabae57e up to, but not including, 85fa3512048793076eef658f66489112dcc91993; and 1 more ranges | ea18732d2614557e59f4c0d8cdbe6611aeab33b7, d28311539ac9f65e29308ea219ecaa48aa5e76e5, b6ae482f88654db407c8c17619d4b62959b903ef, 204028af77a265e31ceb4ba7f643349a3cca72b2, 01a6431766c35dfedb86e0cb5d3fc80c6d604a47, e08d75753db17aa943d7622f09d9c217b5bfd3b8 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 3.7 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.140; 6.7 up to, but not including, 6.12.86; 6.13 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.4 | 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4 |
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
- AdjacentThe attacker must be on the same local network segment.
- 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
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: fix potential UAF in SSP passkey handlers hci_conn lookup and field access must be covered by hdev lock in hci_user_passkey_notify_evt() and hci_keypress_notify_evt(), otherwise the connection can be freed concurrently. Extend the hci_dev_lock critical section to cover all conn usage in both handlers. Keep the existing keypress notification behavior unchanged by routing the early exits through a common unlock path.
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/01a6431766c35dfedb86e0cb5d3fc80c6d604a47
- git.kernel.org/stable/c/204028af77a265e31ceb4ba7f643349a3cca72b2
- git.kernel.org/stable/c/85fa3512048793076eef658f66489112dcc91993
- git.kernel.org/stable/c/8c6443bb9257b780986fb67ec08565bf48ecb8d7
- git.kernel.org/stable/c/b6ae482f88654db407c8c17619d4b62959b903ef
- git.kernel.org/stable/c/e08d75753db17aa943d7622f09d9c217b5bfd3b8
Other references
Recent Use After Free vulnerabilities
- 8.1 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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