Executive Summary
| Informations | |||
|---|---|---|---|
| Name | CVE-2021-47640 | First vendor Publication | 2025-02-26 |
| Vendor | Cve | Last vendor Modification | 2025-03-18 |
Security-Database Scoring CVSS v3
| Cvss vector : CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | |||
|---|---|---|---|
| Overall CVSS Score | 7.8 | ||
| Base Score | 7.8 | Environmental Score | 7.8 |
| impact SubScore | 5.9 | Temporal Score | 7.8 |
| Exploitabality Sub Score | 1.8 | ||
| Attack Vector | Local | Attack Complexity | Low |
| Privileges Required | Low | User Interaction | None |
| Scope | Unchanged | Confidentiality Impact | High |
| Integrity Impact | High | Availability Impact | High |
| Calculate full CVSS 3.0 Vectors scores | |||
Security-Database Scoring CVSS v2
| Cvss vector : | |||
|---|---|---|---|
| Cvss Base Score | N/A | Attack Range | N/A |
| Cvss Impact Score | N/A | Attack Complexity | N/A |
| Cvss Expoit Score | N/A | Authentication | N/A |
| Calculate full CVSS 2.0 Vectors scores | |||
Detail
| In the Linux kernel, the following vulnerability has been resolved: powerpc/kasan: Fix early region not updated correctly The shadow's page table is not updated when PTE_RPN_SHIFT is 24 and PAGE_SHIFT is 12. It not only causes false positives but also false negative as shown the following text. Fix it by bringing the logic of kasan_early_shadow_page_entry here. 1. False Positive: ================================================================== BUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x508/0xa50 Write of size 16 at addr f57f3be0 by task swapper/0/1 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-12267-gdebe436e77c7 #1 Call Trace: [c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (unreliable) [c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300 [c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200 [c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0 [c80d1cc0] [c03018a4] memset+0x34/0x90 [c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50 [c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570 [c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0 [c80d1db0] [c2036580] init_sd+0xc4/0x1d0 [c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c [c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384 [c80d1ef0] [c0004b14] kernel_init+0x24/0x170 [c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64 Memory state around the buggy address: 2. False Negative (with KASAN tests): ================================================================== Before fix: ================================================================== After fix: |
Original Source
| Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-47640 |
CWE : Common Weakness Enumeration
| % | Id | Name |
|---|---|---|
| 100 % | CWE-787 | Out-of-bounds Write (CWE/SANS Top 25) |
CPE : Common Platform Enumeration
Sources (Detail)
Alert History
| Date | Informations |
|---|---|
| 2025-03-29 02:58:09 |
|
| 2025-03-28 13:28:34 |
|
| 2025-03-28 02:42:57 |
|
| 2025-03-18 21:21:39 |
|
| 2025-02-26 17:20:34 |
|
