Linux: Use After Free
CVE-2026-23306 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 ebbb852ffbc952b95ddb7e3872b67b3e74c6da47, 8b00427317ba7b7ec91252b034009f638d0f311b, c5dc39f8ae055520fd778b7fb0423f11586f15c4 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 ebbb852ffbc952b95ddb7e3872b67b3e74c6da47 or 8b00427317ba7b7ec91252b034009f638d0f311b or c5dc39f8ae055520fd778b7fb0423f11586f15c4 or 824a7672e3540962d5c77d4c6666254d7aa6f0b3, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.167 or 6.6.130 or 6.12.77 or 6.18.17, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e29c47fe8946cc732b0e0d393b65b13c84bb69d0 up to, but not including, ebbb852ffbc952b95ddb7e3872b67b3e74c6da47; e29c47fe8946cc732b0e0d393b65b13c84bb69d0 up to, but not including, 8b00427317ba7b7ec91252b034009f638d0f311b; e29c47fe8946cc732b0e0d393b65b13c84bb69d0 up to, but not including, c5dc39f8ae055520fd778b7fb0423f11586f15c4; e29c47fe8946cc732b0e0d393b65b13c84bb69d0 up to, but not including, 824a7672e3540962d5c77d4c6666254d7aa6f0b3; e29c47fe8946cc732b0e0d393b65b13c84bb69d0 up to, but not including, 227ff4af00abc40b95123cc27ee8079069dcd8d7; e29c47fe8946cc732b0e0d393b65b13c84bb69d0 up to, but not including, 38353c26db28efd984f51d426eac2396d299cca7; 5.18 | ebbb852ffbc952b95ddb7e3872b67b3e74c6da47, 8b00427317ba7b7ec91252b034009f638d0f311b, c5dc39f8ae055520fd778b7fb0423f11586f15c4, 824a7672e3540962d5c77d4c6666254d7aa6f0b3, 227ff4af00abc40b95123cc27ee8079069dcd8d7, 38353c26db28efd984f51d426eac2396d299cca7 |
| Linux | Linux Kernel | 5.18 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.77; 6.13 up to, but not including, 6.18.17; 6.19 up to, but not including, 6.19.7; 7.0 | 6.1.167, 6.6.130, 6.12.77, 6.18.17, 6.19.7 |
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 CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: scsi: pm8001: Fix use-after-free in pm8001_queue_command() Commit e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()") refactors pm8001_queue_command(), however it introduces a potential cause of a double free scenario when it changes the function to return -ENODEV in case of phy down/device gone state. In this path, pm8001_queue_command() updates task status and calls task_done to indicate to upper layer that the task has been handled. However, this also frees the underlying SAS task. A -ENODEV is then returned to the caller. When libsas sas_ata_qc_issue() receives this error value, it assumes the task wasn't handled/queued by LLDD and proceeds to clean up and free the task again, resulting in a double free. Since pm8001_queue_command() handles the SAS task in this case, it should return 0 to the caller indicating that the task has been handled.
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
- git.kernel.org/stable/c/227ff4af00abc40b95123cc27ee8079069dcd8d7
- git.kernel.org/stable/c/38353c26db28efd984f51d426eac2396d299cca7
- git.kernel.org/stable/c/824a7672e3540962d5c77d4c6666254d7aa6f0b3
- git.kernel.org/stable/c/8b00427317ba7b7ec91252b034009f638d0f311b
- git.kernel.org/stable/c/c5dc39f8ae055520fd778b7fb0423f11586f15c4
- git.kernel.org/stable/c/ebbb852ffbc952b95ddb7e3872b67b3e74c6da47
Recent Use After Free vulnerabilities
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- 7.8 High severity
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