CVE-2026-23298: can: ucan: Fix infinite loop from zero-length messages

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-25 · updated 2026-06-17
Weakness: CWE-835

Description

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.

Affected products

Linux kernel: from 4.19 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.167; from 6.2 before 6.6.130; from 6.7 before 6.12.77; from 6.13 before 6.18.17 — fixed in 5.10.253, 5.15.203, 6.1.167, 6.12.77, 6.18.17, 6.19.7

How to fix

Upgrade to a fixed version: Linux kernel 5.10.253, 5.15.203, 6.1.167, 6.12.77. Check the vendor advisory for mitigations.

References

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