CVE-2023-52568: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: x86/sgx: Resolves SECS reclaim vs. page fault for EAUG race The SGX EPC reclaimer (ksgxd) may reclaim the SECS EPC page for an enclave and set secs.epc_page to NULL. The SECS page is used for EAUG and ELDU in the SGX page fault handler. However, the NULL check for secs.epc_page is only done for ELDU, not EAUG before being used. Fix this by doing the same NULL check and reloading of the SECS page as needed for both EAUG and ELDU. The SECS page holds global enclave metadata. It can only be reclaimed when there are no other enclave pages remaining. At that point, virtually nothing can be done with the enclave until the SECS page is paged back in. An enclave can not run nor generate page faults without a resident SECS page. But it is still possible for a #PF for a non-SECS page to race with paging out the SECS page: when the last resident non-SECS page A triggers a #PF in a non-resident page B, and then page A and the SECS both are paged out before the #PF on B is handled. Hitting this bug requires that race triggered with a #PF for EAUG. Following is a trace when it happens. BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:sgx_encl_eaug_page+0xc7/0x210 Call Trace: ? __kmem_cache_alloc_node+0x16a/0x440 ? xa_load+0x6e/0xa0 sgx_vma_fault+0x119/0x230 __do_fault+0x36/0x140 do_fault+0x12f/0x400 __handle_mm_fault+0x728/0x1110 handle_mm_fault+0x105/0x310 do_user_addr_fault+0x1ee/0x750 ? __this_cpu_preempt_check+0x13/0x20 exc_page_fault+0x76/0x180 asm_exc_page_fault+0x27/0x30

Is your site exposed to CVE-2023-52568?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

4.7

MEDIUM

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.0 — 6.1.56
linux	linux_kernel	6.2 — 6.5.6
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/1348f7f15d7c7798456856bee74a4235c2da994e https://git.kernel.org/stable/c/811ba2ef0cb6402672e64ba1419d6ef95aa3405d https://git.kernel.org/stable/c/c6c2adcba50c2622ed25ba5d5e7f05f584711358 https://git.kernel.org/stable/c/1348f7f15d7c7798456856bee74a4235c2da994e https://git.kernel.org/stable/c/811ba2ef0cb6402672e64ba1419d6ef95aa3405d https://git.kernel.org/stable/c/c6c2adcba50c2622ed25ba5d5e7f05f584711358

Frequently Asked Questions

What is CVE-2023-52568? +

In the Linux kernel, the following vulnerability has been resolved: x86/sgx: Resolves SECS reclaim vs. page fault for EAUG race The SGX EPC reclaimer (ksgxd) may reclaim the SECS EPC page for an enclave and set secs.epc_page to NULL. The SECS page is used for EAUG and ELDU in the SGX page fault handler. However, the NULL check for secs.epc_page is only done for ELDU, not EAUG before being used. Fix this by doing the same NULL check and reloading of the SECS page as needed for both EAUG and ELDU. The SECS page holds global enclave metadata. It can only be reclaimed when there are no other enclave pages remaining. At that point, virtually nothing can be done with the enclave until the SECS page is paged back in. An enclave can not run nor generate page faults without a resident SECS page. But it is still possible for a #PF for a non-SECS page to race with paging out the SECS page: when the last resident non-SECS page A triggers a #PF in a non-resident page B, and then page A and the SECS both are paged out before the #PF on B is handled. Hitting this bug requires that race triggered with a #PF for EAUG. Following is a trace when it happens. BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:sgx_encl_eaug_page+0xc7/0x210 Call Trace: ? __kmem_cache_alloc_node+0x16a/0x440 ? xa_load+0x6e/0xa0 sgx_vma_fault+0x119/0x230 __do_fault+0x36/0x140 do_fault+0x12f/0x400 __handle_mm_fault+0x728/0x1110 handle_mm_fault+0x105/0x310 do_user_addr_fault+0x1ee/0x750 ? __this_cpu_preempt_check+0x13/0x20 exc_page_fault+0x76/0x180 asm_exc_page_fault+0x27/0x30 It has a CVSS v3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2023-52568? +

CVE-2023-52568 has a CVSS v3.1 score of 4.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2023-52568? +

CVE-2023-52568 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-52568? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-8479

IEC 60870-5-104 used in bidirectional mode in RTU500 is vulnerable for a NULL pointer dereferencing, if a specially crafted sequence …

CVE-2025-24031

PAM-PKCS#11 is a Linux-PAM login module that allows a X.509 certificate based user login. In versions 0.6.12 and prior, the …

CVE-2025-31115

XZ Utils provide a general-purpose data-compression library plus command-line tools. In XZ Utils 5.3.3alpha to 5.8.0, the multithreaded .xz decoder …

CVE-2025-0121

A null pointer dereference vulnerability in the Palo Alto Networks Cortex® XDR agent on Windows devices allows a low-privileged local …

CVE-2023-45925

GNU Midnight Commander 4.8.29-146-g299d9a2fb was discovered to contain a NULL pointer dereference via the function x_error_handler() at tty/x11conn.c. NOTE: this …

CVE-2025-6398

A null pointer dereference vulnerability exists in the IOMap64.sys driver of ASUS AI Suite 3. The vulnerability can be triggered …

CVE-2023-52568