Linux Kernel up to 7.2.5 fat fat_rebuild_parent buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k1.21+

Summaryinfo

A vulnerability described as very critical has been identified in Linux Kernel up to 7.2.5. The affected element is the function fat_rebuild_parent of the component fat. Executing a manipulation can lead to buffer overflow. This vulnerability is tracked as CVE-2026-90318. 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 7.2.5. It has been declared as very critical. This vulnerability affects the function fat_rebuild_parent of the component fat. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: fat: release buffer head after rebuilding parent fat_scan_logstart() leaves the matching directory entry's buffer head in sinfo.bh for the caller to release, just like fat_scan(). fat_rebuild_parent() uses the directory entry to rebuild the parent inode for the nostale_ro NFS export path, but does not release sinfo.bh after a successful scan. Release it once fat_build_inode() has consumed the directory entry data.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-90318 since 09/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/17/2026).

Upgrading to version 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch 5e44b6944e11fd6647f028219ad0be4e85e9acee/d2a86329152c69a6200c15b2bf618755f8563826/0f18d712ba9c980e05b7e33a27cde4fe3ed2d393/e38587d98d1ceac608420052c0cdd901d25878f3/c6a67aa438179cad40f8ae45469e304338d65c0a/571ea4263d69df1b48578e4314a828ecd0604755/7565e44507634514e3e1899d3acad3de43f7a2c1/83e98dbf19ab64e8528e101e20f8d50e1aaa68a8 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
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 5.10.270/5.15.221/6.1.188/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: 5e44b6944e11fd6647f028219ad0be4e85e9acee/d2a86329152c69a6200c15b2bf618755f8563826/0f18d712ba9c980e05b7e33a27cde4fe3ed2d393/e38587d98d1ceac608420052c0cdd901d25878f3/c6a67aa438179cad40f8ae45469e304338d65c0a/571ea4263d69df1b48578e4314a828ecd0604755/7565e44507634514e3e1899d3acad3de43f7a2c1/83e98dbf19ab64e8528e101e20f8d50e1aaa68a8

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90318 (🔒)
GCVE (CVE): GCVE-0-2026-90318
GCVE (VulDB): GCVE-100-406852

Entryinfo

Created: 09/17/2026 21:34
Changes: 09/17/2026 21:34 (59)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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