CVE-2023-53699

  • Published: 2025-10-22T14:15:44.437
  • Last modified: 1761167568

In the Linux kernel, the following vulnerability has been resolved:

riscv: move memblock_allow_resize() after linear mapping is ready

The initial memblock metadata is accessed from kernel image mapping. The
regions arrays need to “reallocated” from memblock and accessed through
linear mapping to cover more memblock regions. So the resizing should
not be allowed until linear mapping is ready. Note that there are
memblock allocations when building linear mapping.

This patch is similar to 24cc61d8cb5a (“arm64: memblock: don’t permit
memblock resizing until linear mapping is up”).

In following log, many memblock regions are reserved before
create_linear_mapping_page_table(). And then it triggered reallocation
of memblock.reserved.regions and memcpy the old array in kernel image
mapping to the new array in linear mapping which caused a page fault.

[ 0.000000] memblock_reserve: [0x00000000bf01f000-0x00000000bf01ffff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf021000-0x00000000bf021fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf023000-0x00000000bf023fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf025000-0x00000000bf025fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf027000-0x00000000bf027fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf029000-0x00000000bf029fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf02b000-0x00000000bf02bfff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf02d000-0x00000000bf02dfff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf02f000-0x00000000bf02ffff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] memblock_reserve: [0x00000000bf030000-0x00000000bf030fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6
[ 0.000000] OF: reserved mem: 0x0000000080000000..0x000000008007ffff (512 KiB) map non-reusable mmode_resv0@80000000
[ 0.000000] memblock_reserve: [0x00000000bf000000-0x00000000bf001fed] paging_init+0x19a/0x5ae
[ 0.000000] memblock_phys_alloc_range: 4096 bytes align=0x1000 from=0x0000000000000000 max_addr=0x0000000000000000 alloc_pmd_fixmap+0x14/0x1c
[ 0.000000] memblock_reserve: [0x000000017ffff000-0x000000017fffffff] memblock_alloc_range_nid+0xb8/0x128
[ 0.000000] memblock: reserved is doubled to 256 at [0x000000017fffd000-0x000000017fffe7ff]
[ 0.000000] Unable to handle kernel paging request at virtual address ff600000ffffd000
[ 0.000000] Oops [#1]
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.4.0-rc1-00011-g99a670b2069c #66
[ 0.000000] Hardware name: riscv-virtio,qemu (DT)
[ 0.000000] epc : __memcpy+0x60/0xf8
[ 0.000000] ra : memblock_double_array+0x192/0x248
[ 0.000000] epc : ffffffff8081d214 ra : ffffffff80a3dfc0 sp : ffffffff81403bd0
[ 0.000000] gp : ffffffff814fbb38 tp : ffffffff8140dac0 t0 : 0000000001600000
[ 0.000000] t1 : 0000000000000000 t2 : 000000008f001000 s0 : ffffffff81403c60
[ 0.000000] s1 : ffffffff80c0bc98 a0 : ff600000ffffd000 a1 : ffffffff80c0bcd8
[ 0.000000] a2 : 0000000000000c00 a3 : ffffffff80c0c8d8 a4 : 0000000080000000
[ 0.000000] a5 : 0000000000080000 a6 : 0000000000000000 a7 : 0000000080200000
[ 0.000000] s2 : ff600000ffffd000 s3 : 0000000000002000 s4 : 0000000000000c00
[ 0.000000] s5 : ffffffff80c0bc60 s6 : ffffffff80c0bcc8 s7 : 0000000000000000
[ 0.000000] s8 : ffffffff814fd0a8 s9 : 000000017fffe7ff s10: 0000000000000000
[ 0.000000] s11: 0000000000001000 t3 : 0000000000001000 t4 : 0000000000000000
[ 0.000000] t5 : 000000008f003000 t6 : ff600000ffffd000
[ 0.000000] status: 0000000200000100 badaddr: ff600000ffffd000 cause: 000000000000000f
[ 0.000000] [<fff
—truncated—

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How to fix CVE-2023-53699

CVE-2023-53699 is a unknown severity vulnerability affecting the affected product.

Description: In the Linux kernel, the following vulnerability has been resolved: riscv: move memblock_allow_resize() after linear mapping is ready The initial memblock metadata is accessed from kernel image mapping. The regions arrays need to “reallocated” from memblock and accessed through linear mapping to cover more memblock regions. So the resizing should not be allowed until linear […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Oct 22, 2025
Vulnerability Published

CVE details first published to NVD database

Jan 01, 1970
Last Modified

CVE details were updated

Oct 28, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.