Linux Kernel up to 6.12.109/6.18.50/7.2.4 f2fs set_task_ioprio null pointer dereference

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4.0	$0-$5k	0.00

Summaryinfo

A vulnerability labeled as problematic has been found in Linux Kernel up to 6.12.109/6.18.50/7.2.4. This affects the function set_task_ioprio of the component f2fs. The manipulation results in null pointer dereference. This vulnerability is known as CVE-2026-89835. Attacking locally is a requirement. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.12.109/6.18.50/7.2.4. Affected is the function set_task_ioprio of the component f2fs. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as 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. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: f2fs: avoid NULL checkpoint thread access in sysfs checkpoint_merge can be enabled even when no checkpoint merge thread is running. A read-only mount is one case: f2fs does not start f2fs_issue_ckpt there, but ckpt_thread_ioprio is still writable through sysfs. The ckpt_thread_ioprio store path updates the saved ioprio value and, when checkpoint_merge is enabled, calls set_task_ioprio() for the checkpoint thread. If cprc->f2fs_issue_ckpt is NULL, that dereferences a NULL task pointer. Protect ckpt_thread_ioprio sysfs writes with s_umount as well, so the checkpoint thread cannot disappear under the store path while updating its ioprio.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-89835 since 09/11/2026. The exploitability is told to be easy. The attack needs to be approached locally. The exploitation requires an enhanced level of successful authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version 6.12.110, 6.18.51, 7.2.5 or 7.3-rc1 eliminates this vulnerability. Applying the patch a6573f3ffc19542de9ebc1a2b1f930fd48ba538c/aefcec3bebdeed2bff444378122300763325ba23/8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b/5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f 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

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.109
• 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
• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4

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: 4.2
VulDB Meta Temp Score: 4.0

VulDB Base Score: 4.2
VulDB Temp Score: 4.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

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

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

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

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 6.12.110/6.18.51/7.2.5/7.3-rc1
Patch: a6573f3ffc19542de9ebc1a2b1f930fd48ba538c/aefcec3bebdeed2bff444378122300763325ba23/8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b/5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f

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-2026-89835 (🔒)
GCVE (CVE): GCVE-0-2026-89835
GCVE (VulDB): GCVE-100-405660

Entryinfo

Created: 09/16/2026 13:25
Changes: 09/16/2026 13:25 (59)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

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