Linux Kernel up to 7.2.5 blk-cgroup blkcg_activate_policy use after free

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.
8.7	$5k-$25k	0.39

Summaryinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.2.5. Affected is the function blkcg_activate_policy of the component blk-cgroup. This manipulation causes use after free. This vulnerability is tracked as CVE-2026-90325. The attack is possible to be carried out remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.2.5 and classified as very critical. Affected by this vulnerability is the function blkcg_activate_policy of the component blk-cgroup. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. 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: blk-cgroup: skip dying blkg in blkcg_activate_policy() When switching IO schedulers on a block device, blkcg_activate_policy() can race with concurrent blkcg deletion, leading to a use-after-free in rcu_accelerate_cbs. T1: T2: blkg_destroy kill(&blkg->refcnt) // blkg->refcnt=1->0 blkg_release // call_rcu(__blkg_release) ... blkg_free_workfn ->pd_free_fn(pd) elv_iosched_store elevator_switch ... iterate blkg list blkg_get(blkg) // blkg->refcnt=0->1 list_del_init(&blkg->q_node) blkg_put(pinned_blkg) // blkg->refcnt=1->0 blkg_release // call_rcu again rcu_accelerate_cbs // uaf Fix this by checking hlist_unhashed(&blkg->blkcg_node) before getting a reference to the blkg. This is the same check used in blkg_destroy() to detect if a blkg has already been destroyed. If the blkg is already unhashed, skip processing it since it's being destroyed.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-90325 since 09/11/2026. The exploitation appears to be easy. The attack can be launched remotely. Additional levels of successful authentication are required for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 6.1.17, 6.2.4, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch b5dae1cd0d8368b4338430ff93403df67f0b8bcc/083b58373463a6e5ee60ecb135269348f68ad7df/1a267295b1ea6a6477963f3fda84adfecd48fcad/7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d/3d8c3da95c75a4d312e272fc7b4076dd3ba9115c/d8c872901e6459339374e9eea80aa919176c2ccd/5e9220389920f33b6a804d50c548cd0cd1b04634 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

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.2.0
• 6.2.1
• 6.2.2
• 6.2.3
• 6.6.156
• 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
• 6.18.51
• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

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: 9.1
VulDB Meta Temp Score: 8.7

VulDB Base Score: 9.1
VulDB Temp Score: 8.7
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: Use after free
CWE: CWE-416 / 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 6.1.17/6.2.4/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: b5dae1cd0d8368b4338430ff93403df67f0b8bcc/083b58373463a6e5ee60ecb135269348f68ad7df/1a267295b1ea6a6477963f3fda84adfecd48fcad/7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d/3d8c3da95c75a4d312e272fc7b4076dd3ba9115c/d8c872901e6459339374e9eea80aa919176c2ccd/5e9220389920f33b6a804d50c548cd0cd1b04634

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-2026-90325 (🔒)
GCVE (CVE): GCVE-0-2026-90325
GCVE (VulDB): GCVE-100-406867

Entryinfo

Created: 09/17/2026 21:39
Changes: 09/17/2026 21:39 (59)
Complete: 🔍
Cache ID: 216::103

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Discussion

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