CVE-2021-47623

MEDIUM EPSS 13.1%
Published Jul 16, 20241y ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Jul 16, 2024 1y ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/fixmap: Fix VM debug warning on unmap Unmapping a fixmap entry is done by calling __set_fixmap() with FIXMAP_PAGE_CLEAR as flags. Today, powerpc __set_fixmap() calls map_kernel_page(). map_kernel_page() is not happy when called a second time for the same page. WARNING: CPU: 0 PID: 1 at arch/powerpc/mm/pgtable.c:194 set_pte_at+0xc/0x1e8 CPU: 0 PID: 1 Comm: swapper Not tainted 5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty #682 NIP: c0017cd4 LR: c00187f0 CTR: 00000010 REGS: e1011d50 TRAP: 0700 Not tainted (5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty) MSR: 00029032 <EE,ME,IR,DR,RI> CR: 42000208 XER: 00000000 GPR00: c0165fec e1011e10 c14c0000 c0ee2550 ff800000 c0f3d000 00000000 c001686c GPR08: 00001000 b00045a9 00000001 c0f58460 c0f50000 00000000 c0007e10 00000000 GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 GPR24: 00000000 00000000 c0ee2550 00000000 c0f57000 00000ff8 00000000 ff800000 NIP [c0017cd4] set_pte_at+0xc/0x1e8 LR [c00187f0] map_kernel_page+0x9c/0x100 Call Trace: [e1011e10] [c0736c68] vsnprintf+0x358/0x6c8 (unreliable) [e1011e30] [c0165fec] __set_fixmap+0x30/0x44 [e1011e40] [c0c13bdc] early_iounmap+0x11c/0x170 [e1011e70] [c0c06cb0] ioremap_legacy_serial_console+0x88/0xc0 [e1011e90] [c0c03634] do_one_initcall+0x80/0x178 [e1011ef0] [c0c0385c] kernel_init_freeable+0xb4/0x250 [e1011f20] [c0007e34] kernel_init+0x24/0x140 [e1011f30] [c0016268] ret_from_kernel_thread+0x5c/0x64 Instruction dump: 7fe3fb78 48019689 80010014 7c630034 83e1000c 5463d97e 7c0803a6 38210010 4e800020 81250000 712a0001 41820008 <0fe00000> 9421ffe0 93e1001c 48000030 Implement unmap_kernel_page() which clears an existing pte.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
13.1% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 4

VendorProductVersionRange
linuxlinux_kernel* <5.10.101
linuxlinux_kernel*≥5.11  –  <5.15.24
linuxlinux_kernel*≥5.16  –  <5.16.10
linuxlinux_kernel5.17any

References 4

  • git.kernel.org https://git.kernel.org/stable/c/033fd42c18d9b2121595b6f1e8419a115f9ac5b7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/43ae0ccc4d2722b833fb59b905af129428e06d03
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/67baac10dd5ad1e9f50e8f2659984b3b0728d54e
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/aec982603aa8cc0a21143681feb5f60ecc69d718
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/033fd42c18d9b2121595b6f1e8419a115f9ac5b7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/43ae0ccc4d2722b833fb59b905af129428e06d03
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/67baac10dd5ad1e9f50e8f2659984b3b0728d54e
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/aec982603aa8cc0a21143681feb5f60ecc69d718
    Patch