Executive Summary

Informations
Name CVE-2025-21861 First vendor Publication 2025-03-12
Vendor Cve Last vendor Modification 2025-03-13

Security-Database Scoring CVSS v3

Cvss vector : CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Overall CVSS Score 5.5
Base Score 5.5 Environmental Score 5.5
impact SubScore 3.6 Temporal Score 5.5
Exploitabality Sub Score 1.8
 
Attack Vector Local Attack Complexity Low
Privileges Required Low User Interaction None
Scope Unchanged Confidentiality Impact None
Integrity Impact None 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:

mm/migrate_device: don't add folio to be freed to LRU in migrate_device_finalize()

If migration succeeded, we called folio_migrate_flags()->mem_cgroup_migrate() to migrate the memcg from the old to the new folio. This will set memcg_data of the old folio to 0.

Similarly, if migration failed, memcg_data of the dst folio is left unset.

If we call folio_putback_lru() on such folios (memcg_data == 0), we will add the folio to be freed to the LRU, making memcg code unhappy. Running the hmm selftests:

# ./hmm-tests
...
# RUN hmm.hmm_device_private.migrate ...
[ 102.078007][T14893] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x7ff27d200 pfn:0x13cc00
[ 102.079974][T14893] anon flags: 0x17ff00000020018(uptodate|dirty|swapbacked|node=0|zone=2|lastcpupid=0x7ff)
[ 102.082037][T14893] raw: 017ff00000020018 dead000000000100 dead000000000122 ffff8881353896c9
[ 102.083687][T14893] raw: 00000007ff27d200 0000000000000000 00000001ffffffff 0000000000000000
[ 102.085331][T14893] page dumped because: VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cgroup_disabled())
[ 102.087230][T14893] ------------[ cut here ]------------
[ 102.088279][T14893] WARNING: CPU: 0 PID: 14893 at ./include/linux/memcontrol.h:726 folio_lruvec_lock_irqsave+0x10e/0x170
[ 102.090478][T14893] Modules linked in:
[ 102.091244][T14893] CPU: 0 UID: 0 PID: 14893 Comm: hmm-tests Not tainted 6.13.0-09623-g6c216bc522fd #151
[ 102.093089][T14893] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014
[ 102.094848][T14893] RIP: 0010:folio_lruvec_lock_irqsave+0x10e/0x170
[ 102.096104][T14893] Code: ...
[ 102.099908][T14893] RSP: 0018:ffffc900236c37b0 EFLAGS: 00010293
[ 102.101152][T14893] RAX: 0000000000000000 RBX: ffffea0004f30000 RCX: ffffffff8183f426
[ 102.102684][T14893] RDX: ffff8881063cb880 RSI: ffffffff81b8117f RDI: ffff8881063cb880
[ 102.104227][T14893] RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
[ 102.105757][T14893] R10: 0000000000000001 R11: 0000000000000002 R12: ffffc900236c37d8
[ 102.107296][T14893] R13: ffff888277a2bcb0 R14: 000000000000001f R15: 0000000000000000
[ 102.108830][T14893] FS: 00007ff27dbdd740(0000) GS:ffff888277a00000(0000) knlGS:0000000000000000
[ 102.110643][T14893] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 102.111924][T14893] CR2: 00007ff27d400000 CR3: 000000010866e000 CR4: 0000000000750ef0
[ 102.113478][T14893] PKRU: 55555554
[ 102.114172][T14893] Call Trace:
[ 102.114805][T14893]
[ 102.115397][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170
[ 102.116547][T14893] ? __warn.cold+0x110/0x210
[ 102.117461][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170
[ 102.118667][T14893] ? report_bug+0x1b9/0x320
[ 102.119571][T14893] ? handle_bug+0x54/0x90
[ 102.120494][T14893] ? exc_invalid_op+0x17/0x50
[ 102.121433][T14893] ? asm_exc_invalid_op+0x1a/0x20
[ 102.122435][T14893] ? __wake_up_klogd.part.0+0x76/0xd0
[ 102.123506][T14893] ? dump_page+0x4f/0x60
[ 102.124352][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170
[ 102.125500][T14893] folio_batch_move_lru+0xd4/0x200
[ 102.126577][T14893] ? __pfx_lru_add+0x10/0x10
[ 102.127505][T14893] __folio_batch_add_and_move+0x391/0x720
[ 102.128633][T14893] ? __pfx_lru_add+0x10/0x10
[ 102.129550][T14893] folio_putback_lru+0x16/0x80
[ 102.130564][T14893] migrate_device_finalize+0x9b/0x530
[ 102.131640][T14893] dmirror_migrate_to_device.constprop.0+0x7c5/0xad0
[ 102.133047][T14893] dmirror_fops_unlocked_ioctl+0x89b/0xc80

Likely, nothing else goes wrong: putting the last folio reference will remove the folio from the LRU again. So besides memcg complaining, adding the folio to be freed to the LRU is just an unnecessary step.

The new flow resembles what we have in migrate_folio_move(): add the dst to the lru, rem ---truncated---

Original Source

Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21861

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-416 Use After Free

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 8
Os 3704

Sources (Detail)

https://git.kernel.org/stable/c/069dd21ea8262204f94737878389c2815a054a9e
https://git.kernel.org/stable/c/3f9240d59e9a95d19f06120bfd1d0e681c6c0ac7
https://git.kernel.org/stable/c/41cddf83d8b00f29fd105e7a0777366edc69a5cf
Source Url

Alert History

If you want to see full details history, please login or register.
0
1
2
3
4
5
6
7
Date Informations
2025-03-29 03:46:38
  • Multiple Updates
2025-03-28 13:49:08
  • Multiple Updates
2025-03-28 03:24:30
  • Multiple Updates
2025-03-25 03:30:17
  • Multiple Updates
2025-03-19 00:20:31
  • Multiple Updates
2025-03-18 00:20:34
  • Multiple Updates
2025-03-14 00:20:38
  • Multiple Updates
2025-03-12 13:20:39
  • First insertion