Bug 2464489 (CVE-2026-31750)

Summary: CVE-2026-31750 kernel: comedi: runflags cannot determine whether to reclaim chanlist
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's comedi driver. An exceptional exit case in the do_cmd_ioctl() function, where a runflags variable is not properly set, prevents the chanlist memory from being freed. This memory leak can lead to a denial of service (DoS) condition, potentially impacting system stability and availability.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description OSIDB Bzimport 2026-05-01 15:09:39 UTC
In the Linux kernel, the following vulnerability has been resolved:

comedi: runflags cannot determine whether to reclaim chanlist

syzbot reported a memory leak [1], because commit 4e1da516debb ("comedi:
Add reference counting for Comedi command handling") did not consider
the exceptional exit case in do_cmd_ioctl() where runflags is not set.
This caused chanlist not to be properly freed by do_become_nonbusy(),
as it only frees chanlist when runflags is correctly set.

Added a check in do_become_nonbusy() for the case where runflags is not
set, to properly free the chanlist memory.

[1]
BUG: memory leak
  backtrace (crc 844a0efa):
    __comedi_get_user_chanlist drivers/comedi/comedi_fops.c:1815 [inline]
    do_cmd_ioctl.part.0+0x112/0x350 drivers/comedi/comedi_fops.c:1890
    do_cmd_ioctl drivers/comedi/comedi_fops.c:1858 [inline]