Linux Kernel up to 6.6.127/6.12.74/6.18.15/6.19.5 cifs cifs_tcp_ses_lock privilege escalation

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.6.127/6.12.74/6.18.15/6.19.5 and classified as critical. Affected by this issue is the function cifs_tcp_ses_lock of the component cifs. This manipulation causes an unknown weakness. This vulnerability appears as CVE-2026-43215. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.127/6.12.74/6.18.15/6.19.5. It has been declared as critical. Affected by this vulnerability is the function cifs_tcp_ses_lock of the component cifs. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix locking usage for tcon fields We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization. There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-43215 since 05/01/2026. 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 06/04/2026).

The vulnerability scanner Nessus provides a plugin with the ID 318589 (Oracle Linux 10 / 9 : Unbreakable Enterprise kernel (ELSA-2026-50293)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.128, 6.12.75, 6.18.16 or 6.19.6 eliminates this vulnerability. Applying the patch 953953abb66e52c224057ab91e404284fefeab62/601dd3b79769b38d30b693c40afdb2a4b7edf9d0/3969db6b22e3d90d8c5f22ac1a7fe0350a94c136/8c59eeeeffa1524ef57e173a89a1a3ff539888d5/96c4af418586ee9a6aab61738644366426e05316 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (318589). 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: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 318589
Nessus Name: Oracle Linux 10 / 9 : Unbreakable Enterprise kernel (ELSA-2026-50293)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.128/6.12.75/6.18.16/6.19.6
Patch: 953953abb66e52c224057ab91e404284fefeab62/601dd3b79769b38d30b693c40afdb2a4b7edf9d0/3969db6b22e3d90d8c5f22ac1a7fe0350a94c136/8c59eeeeffa1524ef57e173a89a1a3ff539888d5/96c4af418586ee9a6aab61738644366426e05316

Timelineinfo

05/01/2026 CVE reserved
05/06/2026 +5 days Advisory disclosed
05/06/2026 +0 days VulDB entry created
06/04/2026 +29 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43215 (🔒)
GCVE (CVE): GCVE-0-2026-43215
GCVE (VulDB): GCVE-100-361483

Entryinfo

Created: 05/06/2026 16:54
Updated: 06/04/2026 14:47
Changes: 05/06/2026 16:54 (58), 06/04/2026 14:47 (2)
Complete: 🔍
Cache ID: 216::103

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

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