Linux Kernel up to 6.6.156/6.12.109/6.18.50/7.2.4 f2fs f2fs_xattr_advise_set privileges management

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.00

Summaryinfo

A vulnerability described as very critical has been identified in Linux Kernel up to 6.6.156/6.12.109/6.18.50/7.2.4. This issue affects the function f2fs_xattr_advise_set of the component f2fs. Such manipulation leads to privileges management. This vulnerability is uniquely identified as CVE-2026-89839. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.156/6.12.109/6.18.50/7.2.4 and classified as very critical. Affected by this issue is the function f2fs_xattr_advise_set of the component f2fs. The manipulation with an unknown input leads to a privileges management vulnerability. Using CWE to declare the problem leads to CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set() f2fs_xattr_advise_set() calls inode_owner_or_capable() with &nop_mnt_idmap before allowing the "system.advise" xattr to be set, instead of the idmap that the VFS passes to the ->set() handler. f2fs supports idmapped mounts, so on such a mount this checks the caller's fsuid against the unmapped on-disk owner rather than the mapped owner: the actual owner can be wrongly denied with -EPERM and an unrelated caller wrongly allowed. Pass the handler's idmap instead.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-89839 since 09/11/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 09/16/2026). This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

Upgrading to version 6.6.157, 6.12.110, 6.18.51, 7.2.5 or 7.3-rc1 eliminates this vulnerability. Applying the patch 4c0c610b480cfbc57528aa1acbd6be12ed2a6fb1/c3e2692c7a58e0bdb84bd658d827e89dcecea3ad/3b681229e9f8fb1dd29bc65983bf3c87779e4ca3/ab31e3b774f5d06b4489cef6c297b48c47c9dcbd/a54ffce4637acb0db8e695188a6c7f99f14c3576 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Privileges management
CWE: CWE-269 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
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 6.6.157/6.12.110/6.18.51/7.2.5/7.3-rc1
Patch: 4c0c610b480cfbc57528aa1acbd6be12ed2a6fb1/c3e2692c7a58e0bdb84bd658d827e89dcecea3ad/3b681229e9f8fb1dd29bc65983bf3c87779e4ca3/ab31e3b774f5d06b4489cef6c297b48c47c9dcbd/a54ffce4637acb0db8e695188a6c7f99f14c3576

Timelineinfo

09/11/2026 CVE reserved
09/16/2026 +5 days Advisory disclosed
09/16/2026 +0 days VulDB entry created
09/16/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-89839 (🔒)
GCVE (CVE): GCVE-0-2026-89839
GCVE (VulDB): GCVE-100-405662

Entryinfo

Created: 09/16/2026 13:26
Changes: 09/16/2026 13:26 (59)
Complete: 🔍
Cache ID: 216::103

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