# CVE-2025-22121

## Summary

- **CVE ID:** CVE-2025-22121
- **Severity:** HIGH
- **CVSS Score:** 8.4 (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Apr 16, 2025
- **Last Modified:** Sep 8, 2026

## Description

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

ext4: fix out-of-bound read in ext4_xattr_inode_dec_ref_all()

There's issue as follows:
BUG: KASAN: use-after-free in ext4_xattr_inode_dec_ref_all+0x6ff/0x790
Read of size 4 at addr ffff88807b003000 by task syz-executor.0/15172

CPU: 3 PID: 15172 Comm: syz-executor.0
Call Trace:
 __dump_stack lib/dump_stack.c:82 [inline]
 dump_stack+0xbe/0xfd lib/dump_stack.c:123
 print_address_description.constprop.0+0x1e/0x280 mm/kasan/report.c:400
 __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560
 kasan_report+0x3a/0x50 mm/kasan/report.c:585
 ext4_xattr_inode_dec_ref_all+0x6ff/0x790 fs/ext4/xattr.c:1137
 ext4_xattr_delete_inode+0x4c7/0xda0 fs/ext4/xattr.c:2896
 ext4_evict_inode+0xb3b/0x1670 fs/ext4/inode.c:323
 evict+0x39f/0x880 fs/inode.c:622
 iput_final fs/inode.c:1746 [inline]
 iput fs/inode.c:1772 [inline]
 iput+0x525/0x6c0 fs/inode.c:1758
 ext4_orphan_cleanup fs/ext4/super.c:3298 [inline]
 ext4_fill_super+0x8c57/0xba40 fs/ext4/super.c:5300
 mount_bdev+0x355/0x410 fs/super.c:1446
 legacy_get_tree+0xfe/0x220 fs/fs_context.c:611
 vfs_get_tree+0x8d/0x2f0 fs/super.c:1576
 do_new_mount fs/namespace.c:2983 [inline]
 path_mount+0x119a/0x1ad0 fs/namespace.c:3316
 do_mount+0xfc/0x110 fs/namespace.c:3329
 __do_sys_mount fs/namespace.c:3540 [inline]
 __se_sys_mount+0x219/0x2e0 fs/namespace.c:3514
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1

Memory state around the buggy address:
 ffff88807b002f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807b002f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807b003000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807b003080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807b003100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

Above issue happens as ext4_xattr_delete_inode() isn't check xattr
is valid if xattr is in inode.
To solve above issue call xattr_check_inode() check if xattr if valid
in inode. In fact, we can directly verify in ext4_iget_extra_inode(),
so that there is no divergent verification.

## Affected Products

- Linux — Linux (e50e5129f384ae282adebfb561189cdb19b81cee)
- Linux — Linux (4.13)
- Linux — Linux (0)
- Linux — Linux (5.10.248)
- Linux — Linux (5.15.198)
- Linux — Linux (6.1.161)
- Linux — Linux (6.6.120)
- Linux — Linux (6.12.59)
- Linux — Linux (6.14.2)
- Linux — Linux (6.15)

## References

- [CNA](https://git.kernel.org/stable/c/27202452b0bc942fdc3db72a44c4dcdab96d5b56)
- [CNA](https://git.kernel.org/stable/c/b374e9ecc92aaa7fb2ab221ee3ff5451118ab566)
- [CNA](https://git.kernel.org/stable/c/c000a8a9b5343a5ef867df173c6349672dacbd0f)
- [CNA](https://git.kernel.org/stable/c/3c591353956ffcace2cc74d09930774afed60619)
- [CNA](https://git.kernel.org/stable/c/098927a13fd918bd7c64c2de905350a1ad7b4a3a)
- [CNA](https://git.kernel.org/stable/c/0c8fbb6ffb3c8f5164572ca88e4ccb6cd6a41ca8)
- [CNA](https://git.kernel.org/stable/c/5701875f9609b000d91351eaa6bfd97fe2f157f4)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-019113.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.21%
- **EPSS Percentile:** 11.2

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-19._