CVE-2025-22121

CVE-2025-22121 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

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.

Frequently asked questions

What is CVE-2025-22121?
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.
How severe is CVE-2025-22121?
CVE-2025-22121 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2025-22121 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-22121?
CVE-2025-22121 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-22121?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-22121 have an EU (EUVD) identifier?
Yes. CVE-2025-22121 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-11160.
When was CVE-2025-22121 published?
CVE-2025-22121 was published on 2025-04-16 and last updated on 2026-06-17.

References

Affected products (1)

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