Linux Kernel up to 6.18.52/7.2.6/7.3-rc2 netfs fs/netfs/write_issue.c netfs_prepare_write null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k0.16

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.52/7.2.6/7.3-rc2. It has been classified as critical. This affects the function netfs_prepare_write of the file fs/netfs/write_issue.c of the component netfs. This manipulation causes null pointer dereference. The identification of this vulnerability is CVE-2026-98119. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.52/7.2.6/7.3-rc2. It has been declared as critical. Affected by this vulnerability is the function netfs_prepare_write of the file fs/netfs/write_issue.c of the component netfs. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. 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: netfs: break unbuffered write when netfs_alloc_subrequest() fails syzbot reported a null-ptr-deref below [1] following a fault injection in netfs_alloc_subrequest(). [0] When netfs_alloc_subrequest() fails, subreq is NULL. Later, netfs_prepare_write() tries to initialize members of subreq(e.g., source), the issue in [1] is triggered. Let's handle the error of netfs_prepare_write() properly. [0] FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 Call Trace: netfs_alloc_subrequest+0x116/0x3f0 netfs_prepare_write+0x76/0x7b0 netfs_unbuffered_write+0x75c/0x2020 netfs_unbuffered_write_iter_locked+0x7d6/0xa80 netfs_unbuffered_write_iter+0x442/0x720 v9fs_file_write_iter+0xbf/0x100 vfs_write+0x6ac/0x1050 [1] KASAN: null-ptr-deref in range [0x00000000000000a8-0x00000000000000af] RIP: 0010:netfs_prepare_write+0xbc/0x7b0 fs/netfs/write_issue.c:173 Call Trace: netfs_unbuffered_write+0x75c/0x2020 fs/netfs/direct_write.c:111 netfs_unbuffered_write_iter_locked+0x7d6/0xa80 fs/netfs/direct_write.c:290 netfs_unbuffered_write_iter+0x442/0x720 fs/netfs/direct_write.c:382 v9fs_file_write_iter+0xbf/0x100 fs/9p/vfs_file.c:409 new_sync_write fs/read_write.c:595 [inline]

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-98119 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 09/25/2026).

Upgrading to version 6.18.53, 7.2.7 or 7.3-rc3 eliminates this vulnerability. Applying the patch cf6f93b8b06acf57de62dacbe71a3b99c68656a7/19f246c795e940dc5f11cd5bc0cb1e81bc7b7090/8fb45a934661419c04a44d4cfea1e0df7dcf2805 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
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: Null pointer dereference
CWE: CWE-476 / CWE-404
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 6.18.53/7.2.7/7.3-rc3
Patch: cf6f93b8b06acf57de62dacbe71a3b99c68656a7/19f246c795e940dc5f11cd5bc0cb1e81bc7b7090/8fb45a934661419c04a44d4cfea1e0df7dcf2805

Timelineinfo

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

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98119 (🔒)
GCVE (CVE): GCVE-0-2026-98119
GCVE (VulDB): GCVE-100-409939

Entryinfo

Created: 09/25/2026 13:03
Changes: 09/25/2026 13:03 (60)
Complete: 🔍
Cache ID: 216::103

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