Linux Kernel up to 6.18.52 isofs set_blocksize buffer overflow

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.3	$0-$5k	1.57+

Summaryinfo

A vulnerability marked as problematic has been reported in Linux Kernel up to 6.18.52. This affects the function set_blocksize of the component isofs. This manipulation causes buffer overflow. This vulnerability appears as CVE-2026-98879. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.52. It has been declared as problematic. Affected by this vulnerability is the function set_blocksize of the component isofs. 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 availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: isofs: handle set_blocksize failures isofs uses buffer_heads, which don't handle block size > PAGE_SIZE well. Without this, mounting we will hit the BUG_ON(offset >= folio_size(folio)); in folio_set_bh on the first __bread_gfp call.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-98879 since 09/25/2026. The exploitation appears to be easy. The attack can be launched remotely. Additional levels of successful authentication are necessary for exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/23/2026).

Upgrading to version 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111 or 6.18.53 eliminates this vulnerability. Applying the patch 6db7f0ba365786304558db6a3d52013ae176e03e/61f277bf35f533b602984f0e55900111fe52f31a/cebde6d88e34396c29f2f001d90e921677cc17d6/28d1f6aa14f5924e36602b7a31c9141d34de0b9c/9c97e3b1152d3092581745189f5d2f04c6404ef9/9584ab6283721e5aab485c79bd06c2f78d89e55c/25ef4c4d9f0e96fb89c0ae0d7127c3f12a31bc32 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-108673). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.270
• 5.15.221
• 6.1.188
• 6.6.157
• 6.12.110
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 6.18.40
• 6.18.41
• 6.18.42
• 6.18.43
• 6.18.44
• 6.18.45
• 6.18.46
• 6.18.47
• 6.18.48
• 6.18.49
• 6.18.50
• 6.18.51
• 6.18.52

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.5
VulDB Meta Temp Score: 4.3

VulDB Base Score: 4.5
VulDB Temp Score: 4.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.271/5.15.222/6.1.189/6.6.158/6.12.111/6.18.53
Patch: 6db7f0ba365786304558db6a3d52013ae176e03e/61f277bf35f533b602984f0e55900111fe52f31a/cebde6d88e34396c29f2f001d90e921677cc17d6/28d1f6aa14f5924e36602b7a31c9141d34de0b9c/9c97e3b1152d3092581745189f5d2f04c6404ef9/9584ab6283721e5aab485c79bd06c2f78d89e55c/25ef4c4d9f0e96fb89c0ae0d7127c3f12a31bc32

Timelineinfo

09/25/2026 CVE reserved
10/23/2026 +28 days Advisory disclosed
10/23/2026 +0 days VulDB entry created
10/23/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98879 (🔒)
GCVE (CVE): GCVE-0-2026-98879
GCVE (VulDB): GCVE-100-425653
EUVD: 🔒

Entryinfo

Created: 10/23/2026 14:10
Updated: 10/23/2026 14:44
Changes: 10/23/2026 14:10 (59), 10/23/2026 14:44 (1)
Complete: 🔍
Cache ID: 216::103

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