Linux: Use After Free
CVE-2026-46084 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 6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f, f1ccc4d500a0b87a5599343fc2f798048836e184, 8ba804869382ce307f2a15f5f6f2adfd791f41dc 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 0.13% 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 6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f or f1ccc4d500a0b87a5599343fc2f798048836e184 or 8ba804869382ce307f2a15f5f6f2adfd791f41dc or 3be5ed233de03b00ae868cfc06e95331d8d9007c, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.140 or 6.12.86 or 6.18.27 or 7.0.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 0266a177631d4c6b963b5b12dd986a8c5abdbf06 up to, but not including, 6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f; 0266a177631d4c6b963b5b12dd986a8c5abdbf06 up to, but not including, f1ccc4d500a0b87a5599343fc2f798048836e184; 0266a177631d4c6b963b5b12dd986a8c5abdbf06 up to, but not including, 8ba804869382ce307f2a15f5f6f2adfd791f41dc; 0266a177631d4c6b963b5b12dd986a8c5abdbf06 up to, but not including, 3be5ed233de03b00ae868cfc06e95331d8d9007c; 0266a177631d4c6b963b5b12dd986a8c5abdbf06 up to, but not including, dbeb256e8dd87233d891b170c0b32a6466467036; 6.2 | 6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f, f1ccc4d500a0b87a5599343fc2f798048836e184, 8ba804869382ce307f2a15f5f6f2adfd791f41dc, 3be5ed233de03b00ae868cfc06e95331d8d9007c, dbeb256e8dd87233d891b170c0b32a6466467036 |
| Linux | Linux Kernel | 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 | 6.6.140, 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
- 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.
Official description
In the Linux kernel, the following vulnerability has been resolved: RDMA/mana_ib: Disable RX steering on RSS QP destroy When an RSS QP is destroyed (e.g. DPDK exit), mana_ib_destroy_qp_rss() destroys the RX WQ objects but does not disable vPort RX steering in firmware. This leaves stale steering configuration that still points to the destroyed RX objects. If traffic continues to arrive (e.g. peer VM is still transmitting) and the VF interface is subsequently brought up (mana_open), the firmware may deliver completions using stale CQ IDs from the old RX objects. These CQ IDs can be reused by the ethernet driver for new TX CQs, causing RX completions to land on TX CQs: WARNING: mana_poll_tx_cq+0x1b8/0x220 [mana] (is_sq == false) WARNING: mana_gd_process_eq_events+0x209/0x290 (cq_table lookup fails) Fix this by disabling vPort RX steering before destroying RX WQ objects. Note that mana_fence_rqs() cannot be used here because the fence completion is delivered on the CQ, which is polled by user-mode (e.g. DPDK) and not visible to the kernel driver. Refactor the disable logic into a shared mana_disable_vport_rx() in mana_en, exported for use by mana_ib, replacing the duplicate code. The ethernet driver's mana_dealloc_queues() is also updated to call this common function.
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/3be5ed233de03b00ae868cfc06e95331d8d9007c
- git.kernel.org/stable/c/6a2d6273b6c3581ce7b90ce17b5cbb4efd19438f
- git.kernel.org/stable/c/8ba804869382ce307f2a15f5f6f2adfd791f41dc
- git.kernel.org/stable/c/dbeb256e8dd87233d891b170c0b32a6466467036
- git.kernel.org/stable/c/f1ccc4d500a0b87a5599343fc2f798048836e184
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
- 8.8 High severity
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