Linux Kernel up to 7.3-rc3 smb clean_demultiplex_info use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.00-

Summaryinfo

A vulnerability identified as very critical has been detected in Linux Kernel up to 6.6.157/6.12.111/6.18.53/7.2.7/7.3-rc3. The affected element is the function clean_demultiplex_info of the component smb. The manipulation leads to use after free. This vulnerability is documented as CVE-2026-98175. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Linux Kernel up to 6.6.157/6.12.111/6.18.53/7.2.7/7.3-rc3. This issue affects the function clean_demultiplex_info of the component smb. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: smb: client: cancel reconnect work in clean_demultiplex_info() clean_demultiplex_info() cancels server->echo delayed work but not server->reconnect, which can cause a use-after-free when the demultiplex thread exits while a reconnect work is still queued: cifs_demultiplex_thread() cifs_readv_from_socket() cifs_reconnect() __cifs_reconnect() cifs_queue_server_reconn() mod_delayed_work(cifsiod_wq, &server->reconnect, 0) clean_demultiplex_info() cancel_delayed_work_sync(&server->echo) // echo canceled // reconnect NOT canceled kfree_sensitive(server) // server freed ...later, on cifsiod_wq: smb2_reconnect_server() server->srv_count // UAF read of freed server Fix this by canceling server->reconnect delayed work in clean_demultiplex_info() before the server is freed, the same way cifs_put_tcp_session() already does.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-98175 since 09/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/07/2026).

Upgrading to version 6.6.158, 6.12.112, 6.18.54, 7.2.8 or 7.3-rc4 eliminates this vulnerability. Applying the patch 180380272f116dbd2b0354c5c7872e112e519149/e3f6a779433d13aafb5edab59e4f9313051e8a52/7ab9ceedd860216fb97f2d8574cbe58b8906f42a/2e5103e11a17c274715dd56cf185eeedccf686b8/c65eae6f61d1778ff7a82e4aae4080e26f486af1 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 CERT Bund (WID-SEC-2026-3743). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Open Source Linux Kernel

Productinfo

Type

Vendor

Name

Version

License

Website

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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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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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

EPSS Score: 🔒
EPSS Percentile: 🔒

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 6.6.158/6.12.112/6.18.54/7.2.8/7.3-rc4
Patch: 180380272f116dbd2b0354c5c7872e112e519149/e3f6a779433d13aafb5edab59e4f9313051e8a52/7ab9ceedd860216fb97f2d8574cbe58b8906f42a/2e5103e11a17c274715dd56cf185eeedccf686b8/c65eae6f61d1778ff7a82e4aae4080e26f486af1

Timelineinfo

09/25/2026 CVE reserved
10/06/2026 +11 days Advisory disclosed
10/06/2026 +0 days VulDB entry created
10/07/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98175 (🔒)
GCVE (CVE): GCVE-0-2026-98175
GCVE (VulDB): GCVE-100-414101
CERT Bund: WID-SEC-2026-3743 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/06/2026 12:46
Updated: 10/07/2026 00:50
Changes: 10/06/2026 12:46 (59), 10/07/2026 00:50 (7)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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