Linux Kernel up to 6.18.52 btrfs sb_write_pointer/read_cache_page_gfp race condition

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$0-$5k0.41-

Summaryinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 5.15.221/6.1.188/6.6.157/6.12.110/6.18.52. This issue affects the function sb_write_pointer/read_cache_page_gfp of the component btrfs. This manipulation causes race condition. This vulnerability is handled as CVE-2026-98907. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.15.221/6.1.188/6.6.157/6.12.110/6.18.52. It has been declared as very critical. Affected by this vulnerability is the function sb_write_pointer/read_cache_page_gfp of the component btrfs. The manipulation with an unknown input leads to a race condition vulnerability. The CWE definition for the vulnerability is CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: btrfs: protect sb_write_pointer() with invalidate lock sb_write_pointer() reads the super block from the block device page cache using read_cache_page_gfp(). This has the same race with BLKBSZSET as the one fixed by commit 3f29d661e568 ("btrfs: sync read disk super and set block size"). Take the mapping invalidate lock around read_cache_page_gfp() to serialize the read against block size changes.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-98907 since 09/25/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/23/2026).

Upgrading to version 5.15.222, 6.1.189, 6.6.158, 6.12.111 or 6.18.53 eliminates this vulnerability. Applying the patch c9b38f2eab5a9bd74087390318d93ccdd8d2deff/a0dc28359a8a26f970ccd250b126a2e0bd4118a5/1a6c92aa7242a04e4349c0ea213dbf703a1c9891/a58cab4535f085adc0f93d7efd7952ef437371da/80cd97c5e90096d040a623851795eac92fbd0ff1/123b9a545f4d0348e81f558a032bf2a93ee5722f 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-2026-108863). Be aware that VulDB is the high quality 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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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
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 5.15.222/6.1.189/6.6.158/6.12.111/6.18.53
Patch: c9b38f2eab5a9bd74087390318d93ccdd8d2deff/a0dc28359a8a26f970ccd250b126a2e0bd4118a5/1a6c92aa7242a04e4349c0ea213dbf703a1c9891/a58cab4535f085adc0f93d7efd7952ef437371da/80cd97c5e90096d040a623851795eac92fbd0ff1/123b9a545f4d0348e81f558a032bf2a93ee5722f

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-2026-98907 (🔒)
GCVE (CVE): GCVE-0-2026-98907
GCVE (VulDB): GCVE-100-425671
EUVD: 🔒

Entryinfo

Created: 10/23/2026 14:24
Updated: 10/23/2026 15:45
Changes: 10/23/2026 14:24 (59), 10/23/2026 15:45 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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