CVE-2026-23344
Published: 25 March 2026
Summary
CVE-2026-23344 is a high-severity Use After Free (CWE-416) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 5.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and SI-11 (Error Handling).
Deeper analysis
CVE-2026-23344 is a use-after-free vulnerability in the Linux kernel's crypto/ccp component. Specifically, in the error path of the sev_tsm_init_locked() function, the code dereferences a structure pointer 't' after it has been freed via kfree(). The pr_err() statement accesses fields t->tio_en and t->tio_init_done from the already-freed memory. This flaw was identified by the Smatch static analyzer. The vulnerability carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and is classified under CWE-416 (Use After Free).
A local attacker with low privileges can exploit this vulnerability due to its low attack complexity and lack of user interaction requirements. Successful exploitation could result in high impacts to confidentiality, integrity, and availability, potentially allowing arbitrary code execution, data corruption, or system denial of service within the kernel context.
The provided patch references detail the mitigation: kernel commit 79a26fe3175b9ed7c0c9541b197cb9786237c0f7 and 889b0e2721e793eb46cf7d17b965aa3252af3ec8 move the pr_err() call before the kfree(t) to ensure the structure fields are accessed while the memory remains valid, resolving the use-after-free condition. Security practitioners should update to kernels incorporating these stable fixes.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-15311
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Fix use-after-free on error path In the error path of sev_tsm_init_locked(), the code dereferences 't' after it has been freed with kfree(). The pr_err() statement attempts to…
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access t->tio_en and t->tio_init_done after the memory has been released. Move the pr_err() call before kfree(t) to access the fields while the memory is still valid. This issue reported by Smatch static analyser
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel use-after-free in ccp/sev_tsm enables privilege escalation via arbitrary code execution from low-privileged context.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates timely identification, reporting, and patching of kernel flaws like this use-after-free vulnerability.
Implements runtime memory protections such as ASLR and stack canaries that mitigate exploitation of use-after-free errors in the kernel.
Requires secure error handling in functions like sev_tsm_init_locked() to prevent compromises such as dereferencing freed memory.