Linux: Use After Free
CVE-2026-23193 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 2b64015550a13bcc72910be0565548d9a754d46d, fd8b0900173307039d3a84644c2fee041a7ed4fb, d8dbdc146e9e9a976931b78715be2e91299049f9 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 0.36% 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 2b64015550a13bcc72910be0565548d9a754d46d or fd8b0900173307039d3a84644c2fee041a7ed4fb or d8dbdc146e9e9a976931b78715be2e91299049f9 or 11ebafffce31efc6abeb28c509017976fc49f1ca, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.250 or 5.15.200 or 6.1.163 or 6.6.124, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e48354ce078c079996f89d715dfa44814b4eba01 up to, but not including, 2b64015550a13bcc72910be0565548d9a754d46d; e48354ce078c079996f89d715dfa44814b4eba01 up to, but not including, fd8b0900173307039d3a84644c2fee041a7ed4fb; e48354ce078c079996f89d715dfa44814b4eba01 up to, but not including, d8dbdc146e9e9a976931b78715be2e91299049f9; e48354ce078c079996f89d715dfa44814b4eba01 up to, but not including, 11ebafffce31efc6abeb28c509017976fc49f1ca; e48354ce078c079996f89d715dfa44814b4eba01 up to, but not including, 41b86a9ec037bd3435d68dd3692f0891a207e7e7; e48354ce078c079996f89d715dfa44814b4eba01 up to, but not including, 4530f4e4d0e6a207110b0ffed0c911bca43531a4; e48354ce078c079996f89d715dfa44814b4eba01 up to, but not including, 84dc6037390b8607c5551047d3970336cb51ba9a; 3.1 | 2b64015550a13bcc72910be0565548d9a754d46d, fd8b0900173307039d3a84644c2fee041a7ed4fb, d8dbdc146e9e9a976931b78715be2e91299049f9, 11ebafffce31efc6abeb28c509017976fc49f1ca, 41b86a9ec037bd3435d68dd3692f0891a207e7e7, 4530f4e4d0e6a207110b0ffed0c911bca43531a4 |
| Linux | Linux Kernel | 3.1 up to, but not including, 5.10.250; 5.11 up to, but not including, 5.15.200; 5.16 up to, but not including, 6.1.163; 6.2 up to, but not including, 6.6.124; 6.7 up to, but not including, 6.12.70; 6.13 up to, but not including, 6.18.10; 6.19 | 5.10.250, 5.15.200, 6.1.163, 6.6.124, 6.12.70, 6.18.10 |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count() In iscsit_dec_session_usage_count(), the function calls complete() while holding the sess->session_usage_lock. Similar to the connection usage count logic, the waiter signaled by complete() (e.g., in the session release path) may wake up and free the iscsit_session structure immediately. This creates a race condition where the current thread may attempt to execute spin_unlock_bh() on a session structure that has already been deallocated, resulting in a KASAN slab-use-after-free. To resolve this, release the session_usage_lock before calling complete() to ensure all dereferences of the sess pointer are finished before the waiter is allowed to proceed with deallocation.
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/11ebafffce31efc6abeb28c509017976fc49f1ca
- git.kernel.org/stable/c/2b64015550a13bcc72910be0565548d9a754d46d
- git.kernel.org/stable/c/41b86a9ec037bd3435d68dd3692f0891a207e7e7
- git.kernel.org/stable/c/4530f4e4d0e6a207110b0ffed0c911bca43531a4
- git.kernel.org/stable/c/84dc6037390b8607c5551047d3970336cb51ba9a
- git.kernel.org/stable/c/d8dbdc146e9e9a976931b78715be2e91299049f9
- git.kernel.org/stable/c/fd8b0900173307039d3a84644c2fee041a7ed4fb
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
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