Linux Kernel up to 7.0-rc2 ucan ucan_read_bulk_callback length infinite loop

Summaryinfo

A vulnerability has been found in Linux Kernel up to 7.0-rc2 and classified as critical. This issue affects the function ucan_read_bulk_callback of the component ucan. The manipulation of the argument length leads to infinite loop. This vulnerability is uniquely identified as CVE-2026-23298. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 7.0-rc2. This issue affects the function ucan_read_bulk_callback of the component ucan. The manipulation of the argument length with an unknown input leads to a infinite loop vulnerability. Using CWE to declare the problem leads to CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: can: ucan: Fix infinite loop from zero-length messages If a broken ucan device gets a message with the message length field set to 0, then the driver will loop for forever in ucan_read_bulk_callback(), hanging the system. If the length is 0, just skip the message and go on to the next one. This has been fixed in the kvaser_usb driver in the past in commit 0c73772cd2b8 ("can: kvaser_usb: leaf: Fix potential infinite loop in command parsers"), so there must be some broken devices out there like this somewhere.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-23298 since 01/13/2026. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 6.1.167, 6.6.130, 6.12.77, 6.18.17, 6.19.7 or 7.0-rc3 eliminates this vulnerability. Applying the patch ab6f075492d37368b4c7b0df7f7fdc2b666887fc/13b646eec3ba1131180803f5aaf1fee23540ad8f/bd85f21a6219aeae4389d700c54f1799f4b814e0/aa9e0a7fe5efc2f74327fd37d828e9a51d9ff588/c7bc62be6c1a60bb21301692009590b1ffda91d9/1e446fd0582ad8be9f6dafb115fc2e7245f9bea7 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 CERT Bund (WID-SEC-2026-0861). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.166
• 6.6.129
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
• 6.12.64
• 6.12.65
• 6.12.66
• 6.12.67
• 6.12.68
• 6.12.69
• 6.12.70
• 6.12.71
• 6.12.72
• 6.12.73
• 6.12.74
• 6.12.75
• 6.12.76
• 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
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3
• 6.19.4
• 6.19.5
• 6.19.6
• 7.0-rc1
• 7.0-rc2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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CVSSv4info

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Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

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Sourcesinfo

Entryinfo

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

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