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

9p: add missing locking around taking dentry fid list

Fix a use-after-free on dentry's d_fsdata fid list when a thread
looks up a fid through dentry while another thread unlinks it:

UAF thread:
refcount_t: addition on 0; use-after-free.
p9_fid_get linux/./include/net/9p/client.h:262
v9fs_fid_find+0x236/0x280 linux/fs/9p/fid.c:129
v9fs_fid_lookup_with_uid linux/fs/9p/fid.c:181
v9fs_fid_lookup+0xbf/0xc20 linux/fs/9p/fid.c:314
v9fs_vfs_getattr_dotl+0xf9/0x360 linux/fs/9p/vfs_inode_dotl.c:400
vfs_statx+0xdd/0x4d0 linux/fs/stat.c:248

Freed by:
p9_fid_destroy (inlined)
p9_client_clunk+0xb0/0xe0 linux/net/9p/client.c:1456
p9_fid_put linux/./include/net/9p/client.h:278
v9fs_dentry_release+0xb5/0x140 linux/fs/9p/vfs_dentry.c:55
v9fs_remove+0x38f/0x620 linux/fs/9p/vfs_inode.c:518
vfs_unlink+0x29a/0x810 linux/fs/namei.c:4335

The problem is that d_fsdata was not accessed under d_lock, because
d_release() normally is only called once the dentry is otherwise no
longer accessible but since we also call it explicitly in v9fs_remove
that lock is required:
move the hlist out of the dentry under lock then unref its fids once
they are no longer accessible.
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Thu, 17 Oct 2024 14:15:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:o:linux:linux_kernel:5.11:*:*:*:*:*:*:*
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Thu, 17 Oct 2024 14:00:00 +0000


Tue, 10 Sep 2024 07:30:00 +0000

Type Values Removed Values Added
References

Thu, 29 Aug 2024 14:45:00 +0000

Type Values Removed Values Added
Metrics threat_severity

Moderate

threat_severity

Important


Mon, 19 Aug 2024 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.10:rc1:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-05-04T09:16:20.926Z

Reserved: 2024-06-25T14:23:23.744Z

Link: CVE-2024-39463

cve-icon Vulnrichment

Updated: 2024-08-02T04:26:15.245Z

cve-icon NVD

Status : Modified

Published: 2024-06-25T15:15:14.760

Modified: 2024-11-21T09:27:43.050

Link: CVE-2024-39463

cve-icon Redhat

Severity : Important

Publid Date: 2024-06-25T00:00:00Z

Links: CVE-2024-39463 - Bugzilla

cve-icon OpenCVE Enrichment

No data.