Linux: Double Free
CVE-2026-64118 is a high-severity double free vulnerability in Linux, with a CVSS 3.1 base score of 8.4 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. The record lists versions 9fe030719bd083b766602692ee96c8c985798e3c, 06fa8e69019fd3c41a7b0ea8c5f509c3a33dc227, 8cf5e4d2ca6b101d163c7423a426fb0aec34f7bb 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 0.15% 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 9fe030719bd083b766602692ee96c8c985798e3c or 06fa8e69019fd3c41a7b0ea8c5f509c3a33dc227 or 8cf5e4d2ca6b101d163c7423a426fb0aec34f7bb or 3904b993cc17ec5d7c5d3b57dbd0b775dafb9684, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.175 or 6.6.142, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, 9fe030719bd083b766602692ee96c8c985798e3c; fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, 06fa8e69019fd3c41a7b0ea8c5f509c3a33dc227; fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, 8cf5e4d2ca6b101d163c7423a426fb0aec34f7bb; fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, 3904b993cc17ec5d7c5d3b57dbd0b775dafb9684; fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, bdf678a273cadbccc347f331ae2e93ff4d14834c; fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, 0e47fc1c9181ae029e0e35a865cbf2adcbae626c; fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, a04c207f0801abdd23a169b5f902a9845059a65a; fe56b9e6a8d957d6a20729d626027f800c17a2da up to, but not including, 2bccfb8476ca5f3548afbd623dc7a6980d4e77de; and 1 more ranges | 9fe030719bd083b766602692ee96c8c985798e3c, 06fa8e69019fd3c41a7b0ea8c5f509c3a33dc227, 8cf5e4d2ca6b101d163c7423a426fb0aec34f7bb, 3904b993cc17ec5d7c5d3b57dbd0b775dafb9684, bdf678a273cadbccc347f331ae2e93ff4d14834c, 0e47fc1c9181ae029e0e35a865cbf2adcbae626c |
| Linux | Linux Kernel | 4.4 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.142; 6.7 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.1 | 5.10.259, 5.15.210, 6.1.175, 6.6.142, 6.12.92, 6.18.34 |
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
- 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:L/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: qed: fix double free in qed_cxt_tables_alloc() If one of the later PF or VF CID bitmap allocations fails, qed_cid_map_alloc() jumps to cid_map_fail and frees the previously allocated CID bitmaps before returning an error. qed_cxt_tables_alloc() then calls qed_cxt_mngr_free(), which invokes qed_cid_map_free() again. Fix this by setting each CID bitmap pointer to NULL after bitmap_free() to avoid double free. The bug was first flagged by an experimental analysis tool we are developing for kernel memory-management bugs while analyzing v6.13-rc1. The tool is still under development and is not yet publicly available. Manual inspection confirms that the bug is still present in v7.1-rc3. Runtime reproduction was not attempted because exercising the failing allocation path requires device-specific setup.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
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/06fa8e69019fd3c41a7b0ea8c5f509c3a33dc227
- git.kernel.org/stable/c/0e47fc1c9181ae029e0e35a865cbf2adcbae626c
- git.kernel.org/stable/c/2bccfb8476ca5f3548afbd623dc7a6980d4e77de
- git.kernel.org/stable/c/3904b993cc17ec5d7c5d3b57dbd0b775dafb9684
- git.kernel.org/stable/c/8cf5e4d2ca6b101d163c7423a426fb0aec34f7bb
- git.kernel.org/stable/c/9fe030719bd083b766602692ee96c8c985798e3c
- git.kernel.org/stable/c/a04c207f0801abdd23a169b5f902a9845059a65a
- git.kernel.org/stable/c/bdf678a273cadbccc347f331ae2e93ff4d14834c
Recent Double Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 8.7 High severity
- 9.8 Critical severity
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