Linux: Use After Free
CVE-2026-64122 is a critical-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 9.8 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 1604a2d68414aa4cc34faac0b7faa9c14455e8d3, 152295aa7dc2c5e046606f7dadc84fce41136446, 7d260c5d2d89eb2c8c528d54b576b3aae3e20231 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 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to 1604a2d68414aa4cc34faac0b7faa9c14455e8d3 or 152295aa7dc2c5e046606f7dadc84fce41136446 or 7d260c5d2d89eb2c8c528d54b576b3aae3e20231 or 6.18.34, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.34 or 7.0.11, 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 | 4329514c61abefe4961541b128c549b017bab5ad up to, but not including, 1604a2d68414aa4cc34faac0b7faa9c14455e8d3; 83ac0304a2d77519dae1e54c9713cbe1aedf19c9 up to, but not including, 152295aa7dc2c5e046606f7dadc84fce41136446; 83ac0304a2d77519dae1e54c9713cbe1aedf19c9 up to, but not including, 7d260c5d2d89eb2c8c528d54b576b3aae3e20231; 63f9d5fb4d8040077df801ca3270e2f02d55e0d9; 6.18.14 up to, but not including, 6.18.34; 6.19.4 up to, but not including, 6.20; 7.0 | 1604a2d68414aa4cc34faac0b7faa9c14455e8d3, 152295aa7dc2c5e046606f7dadc84fce41136446, 7d260c5d2d89eb2c8c528d54b576b3aae3e20231, 6.18.34, 6.20 |
| Linux | Linux Kernel | 6.18.14 up to, but not including, 6.18.34; 6.19.4 up to, but not including, 7.0.11; 7.1 | 6.18.34, 7.0.11 |
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
- 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:N/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: net/mlx5e: Fix use-after-free in mlx5e_tx_reporter_timeout_recover mlx5e_tx_reporter_timeout_recover() accesses sq->netdev after mlx5e_safe_reopen_channels() has torn down and freed the channel (and its embedded SQs). Replace the three sq->netdev references with priv->netdev which is safe because priv outlives channel teardown. The netdev_err() call already used priv->netdev for this reason; make the trylock/unlock and health_channel_eq_recover calls consistent. This fixes the following KASAN splat: BUG: KASAN: use-after-free in mlx5e_tx_reporter_timeout_recover+0x1dd/0x360 [mlx5_core] Read of size 8 at addr ffff889860ed0b28 by task kworker/u113:2/5277 Call Trace: mlx5e_tx_reporter_timeout_recover+0x1dd/0x360 [mlx5_core] devlink_health_reporter_recover+0xa2/0x150 devlink_health_report+0x254/0x7c0 mlx5e_reporter_tx_timeout+0x297/0x380 [mlx5_core] mlx5e_tx_timeout_work+0x109/0x170 [mlx5_core] process_one_work+0x677/0xf20 worker_thread+0x51f/0xd90 kthread+0x3a5/0x810 ret_from_fork+0x208/0x400 ret_from_fork_asm+0x1a/0x30
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
Recent Use After Free vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
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