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CVE Record

CVE-2025-22121: ext4: fix out-of-bound read in ext4_xattr_inode_dec_ref_all()

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.

HighCVSS 8.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in Linux ext4 filesystem handling can read freed or out-of-bounds memory when processing invalid extended-attribute data. A successful trigger could crash the system or compromise confidentiality and integrity. The supplied CVSS score is 8.4, but the attack vector is local rather than network-based.

Executive priority

Treat as a high-priority kernel update for systems exposed to untrusted ext4 content. Internet-facing status alone does not establish exposure because the vector is local. Accelerate remediation on shared hosts, appliances, and image-processing infrastructure; follow normal prioritized patching elsewhere.

Technical view

ext4 failed to validate inode-resident extended attributes before ext4_xattr_inode_dec_ref_all() processed them during inode deletion and orphan cleanup. KASAN detected a use-after-free read while mounting an ext4 filesystem. The kernel fix performs validation through ext4_iget_extra_inode(), avoiding divergent checks.

Likely exposure

Exposure is most relevant to Linux systems that mount or process ext4 filesystems, especially where untrusted users or workflows can introduce filesystem images or storage media. The bundle lists affected kernel versions beginning with 4.13, but its flattened version data cannot reliably identify every vulnerable distribution package.

Exploitation context

The CVSS vector describes local, low-complexity exploitation requiring no privileges or user interaction, with potentially high confidentiality, integrity, and availability impact. The supplied bundle marks KEV false and provides no evidence of active exploitation. The observed failure came from automated kernel testing.

Researcher notes

The root issue is missing validation of inode-resident xattr metadata before reference-count processing. The trace reaches the flaw through ext4 orphan cleanup during mount. The sources document a use-after-free/out-of-bounds read and upstream fixes, but do not establish practical code execution, a public exploit, or exploitation in the wild.

Mitigation direction

  • Update to a vendor-supported kernel containing the applicable referenced ext4 stable fix.
  • Consult your Linux distribution or appliance vendor for package-specific affected and fixed versions.
  • Restrict untrusted users and services from mounting or supplying ext4 filesystem images until patched.
  • Prioritize systems that ingest removable media, disk images, snapshots, or externally supplied volumes.

Validation and detection

  • Inventory kernel versions and identify systems that mount or inspect ext4 filesystems.
  • Map installed distribution packages to vendor advisories; do not rely solely on upstream version strings.
  • Confirm the installed kernel contains the applicable upstream stable commit or vendor backport.
  • Review kernel logs for KASAN reports, ext4 errors, crashes, or failures during mount and orphan cleanup.
Prepared
Confidence
high
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2025-22121 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
9Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.4CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H2.55.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

8.4High
CVSS 3.1 vector shape for CVE-2025-22121Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe50e5129f384ae282adebfb561189cdb19b81cee, e50e5129f384ae282adebfb561189cdb19b81cee, e50e5129f384ae282adebfb561189cdb19b81cee, e50e5129f384ae282adebfb561189cdb19b81cee, e50e5129f384ae282adebfb561189cdb19b81cee, e50e5129f384ae282adebfb561189cdb19b81cee, e50e5129f384ae282adebfb561189cdb19b81ceeunaffected
LinuxLinux4.13, 0, 5.10.248, 5.15.198, 6.1.161, 6.6.120, 6.12.59, 6.14.2, 6.15affected
Weakness

CWE details

No CWE listed

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