Linux Kernel up to 6.17.3 ext4 ext4_xattr_inode_update_ref reference count

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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.17.3. Affected by this issue is the function ext4_xattr_inode_update_ref of the component ext4. This manipulation causes reference count. This vulnerability is registered as CVE-2025-40190. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.17.3. Affected by this vulnerability is the function ext4_xattr_inode_update_ref of the component ext4. The manipulation with an unknown input leads to a reference count vulnerability. The CWE definition for the vulnerability is CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. As an impact it is known to affect availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ext4: guard against EA inode refcount underflow in xattr update syzkaller found a path where ext4_xattr_inode_update_ref() reads an EA inode refcount that is already <= 0 and then applies ref_change (often -1). That lets the refcount underflow and we proceed with a bogus value, triggering errors like: EXT4-fs error: EA inode <n> ref underflow: ref_count=-1 ref_change=-1 EXT4-fs warning: ea_inode dec ref err=-117 Make the invariant explicit: if the current refcount is non-positive, treat this as on-disk corruption, emit ext4_error_inode(), and fail the operation with -EFSCORRUPTED instead of updating the refcount. Delete the WARN_ONCE() as negative refcounts are now impossible; keep error reporting in ext4_error_inode(). This prevents the underflow and the follow-on orphan/cleanup churn.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2025-40190 since 04/16/2025. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 275359 (Linux Distros Unpatched Vulnerability : CVE-2025-40190), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.301, 5.10.246, 5.15.195, 6.1.157, 6.6.113, 6.12.54, 6.17.4 or 6.18-rc1 eliminates this vulnerability. Applying the patch ea39e712c2f5ae148ee5515798ae03523673e002/1cfb3e4ddbdc8e02e637b8852540bd4718bf4814/505e69f76ac497e788f4ea0267826ec7266b40c8/3d6269028246f4484bfed403c947a114bb583631/79ea7f3e11effe1bd9e753172981d9029133a278/6b879c4c6bbaab03c0ad2a983953bd1410bb165e/440b003f449a4ff2a00b08c8eab9ba5cd28f3943/57295e835408d8d425bef58da5253465db3d6888 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 databases at Tenable (275359) and CERT Bund (WID-SEC-2025-2595). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux

Productinfo

Type

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Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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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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Nessus ID: 275359
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-40190

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.4.301/5.10.246/5.15.195/6.1.157/6.6.113/6.12.54/6.17.4/6.18-rc1
Patch: ea39e712c2f5ae148ee5515798ae03523673e002/1cfb3e4ddbdc8e02e637b8852540bd4718bf4814/505e69f76ac497e788f4ea0267826ec7266b40c8/3d6269028246f4484bfed403c947a114bb583631/79ea7f3e11effe1bd9e753172981d9029133a278/6b879c4c6bbaab03c0ad2a983953bd1410bb165e/440b003f449a4ff2a00b08c8eab9ba5cd28f3943/57295e835408d8d425bef58da5253465db3d6888

Timelineinfo

04/16/2025 CVE reserved
11/13/2025 +211 days Advisory disclosed
11/13/2025 +0 days VulDB entry created
02/07/2026 +86 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40190 (🔒)
GCVE (CVE): GCVE-0-2025-40190
GCVE (VulDB): GCVE-100-332245
CERT Bund: WID-SEC-2025-2595 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 11/13/2025 07:27
Updated: 02/07/2026 20:15
Changes: 11/13/2025 07:27 (59), 11/13/2025 08:18 (1), 11/13/2025 20:02 (2), 11/14/2025 04:54 (7), 12/01/2025 14:33 (1), 12/21/2025 22:01 (1), 02/07/2026 20:15 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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