Linux Kernel up to 6.1.3 ext4 ext4_xattr_block_set reference count

CVSS Meta Temp Score
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CTI Interest Score
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4.6$0-$5k0.74

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.3. It has been classified as critical. This issue affects the function ext4_xattr_block_set of the component ext4. Performing a manipulation results in reference count. This vulnerability is cataloged as CVE-2022-50668. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.1.3. This affects the function ext4_xattr_block_set of the component ext4. The manipulation with an unknown input leads to a reference count vulnerability. CWE is classifying the issue as CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ext4: fix deadlock due to mbcache entry corruption When manipulating xattr blocks, we can deadlock infinitely looping inside ext4_xattr_block_set() where we constantly keep finding xattr block for reuse in mbcache but we are unable to reuse it because its reference count is too big. This happens because cache entry for the xattr block is marked as reusable (e_reusable set) although its reference count is too big. When this inconsistency happens, this inconsistent state is kept indefinitely and so ext4_xattr_block_set() keeps retrying indefinitely. The inconsistent state is caused by non-atomic update of e_reusable bit. e_reusable is part of a bitfield and e_reusable update can race with update of e_referenced bit in the same bitfield resulting in loss of one of the updates. Fix the problem by using atomic bitops instead. This bug has been around for many years, but it became *much* easier to hit after commit 65f8b80053a1 ("ext4: fix race when reusing xattr blocks").

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2022-50668 since 12/09/2025. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 4.19.270, 5.4.229, 5.10.163, 5.15.87, 6.0.18 or 6.1.4 eliminates this vulnerability. Applying the patch efaa0ca678f56d47316a08030b2515678cebbc50/af53065276376750dfac35a7248af18806404c5d/1be16a0c2f10186df505e28b0cc92d7f3366e2a8/5bc0b2fda4b47c86278f7c6d30c211f425bf51cf/127b80cefb941a81255c72f11081123f3a705369/cc1538c693d25e282bed8c54b65c914a04023a78/a44e84a9b7764c72896f7241a0ec9ac7e7ef38dd is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2025-2765). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.6

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Reference count
CWE: CWE-911 / CWE-664
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 4.19.270/5.4.229/5.10.163/5.15.87/6.0.18/6.1.4
Patch: efaa0ca678f56d47316a08030b2515678cebbc50/af53065276376750dfac35a7248af18806404c5d/1be16a0c2f10186df505e28b0cc92d7f3366e2a8/5bc0b2fda4b47c86278f7c6d30c211f425bf51cf/127b80cefb941a81255c72f11081123f3a705369/cc1538c693d25e282bed8c54b65c914a04023a78/a44e84a9b7764c72896f7241a0ec9ac7e7ef38dd

Timelineinfo

12/09/2025 Advisory disclosed
12/09/2025 +0 days CVE reserved
12/09/2025 +0 days VulDB entry created
03/29/2026 +110 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2022-50668 (🔒)
GCVE (CVE): GCVE-0-2022-50668
GCVE (VulDB): GCVE-100-334899
CERT Bund: WID-SEC-2025-2765 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 12/09/2025 07:42
Updated: 03/29/2026 05:59
Changes: 12/09/2025 07:42 (59), 03/29/2026 05:59 (7)
Complete: 🔍
Cache ID: 216:88D:103

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