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VulnerabilityPublished Updated

CVE-2024-36950: Linux kernel · firewire: ohci: mask bus reset interrupts between ISR and bottom half

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 4.4 Medium · fixed in 5.4.0-1130.140~18.04.1 : update Linux kernel when convenient.

Data as of 28 Oct 2026, 10:59 UTC

CVSS 3.1 base score
4.4Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.4.0-1130.140~18.04.1, 5.4.0-1135.142~18.04.1, 5.4.0-1134.143~18.04.1 +73
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 30 May 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-40.40
Fixed in
  • 6.8.0-40.40
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1013.14
Fixed in
  • 6.8.0-1013.14
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1012.14
Fixed in
  • 6.8.0-1012.14
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1012.13
Fixed in
  • 6.8.0-1012.13
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1008.11
Fixed in
  • 6.8.0-1008.11
Ubuntu 24.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1010.10
Fixed in
  • 6.8.0-1010.10

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: firewire: ohci: mask bus reset interrupts between ISR and bottom half In the FireWire OHCI interrupt handler, if a bus reset interrupt has occurred, mask bus reset interrupts until bus_reset_work has serviced and cleared the interrupt. Normally, we always leave bus reset interrupts masked. We infer the bus reset from the self-ID interrupt that happens shortly thereafter. A scenario where we unmask bus reset interrupts was introduced in 2008 in a007bb857e0b26f5d8b73c2ff90782d9c0972620: If OHCI_PARAM_DEBUG_BUSRESETS (8) is set in the debug parameter bitmask, we will unmask bus reset interrupts so we can log them. irq_handler logs the bus reset interrupt. However, we can't clear the bus reset event flag in irq_handler, because we won't service the event until later. irq_handler exits with the event flag still set. If the corresponding interrupt is still unmasked, the first bus reset will usually freeze the system due to irq_handler being called again each time it exits. This freeze can be reproduced by loading firewire_ohci with "modprobe firewire_ohci debug=-1" (to enable all debugging output). Apparently there are also some cases where bus_reset_work will get called soon enough to clear the event, and operation will continue normally. This freeze was first reported a few months after a007bb85 was committed, but until now it was never fixed. The debug level could safely be set to -1 through sysfs after the module was loaded, but this would be ineffectual in logging bus reset interrupts since they were only unmasked during initialization. irq_handler will now leave the event flag set but mask bus reset interrupts, so irq_handler won't be called again and there will be no freeze. If OHCI_PARAM_DEBUG_BUSRESETS is enabled, bus_reset_work will unmask the interrupt after servicing the event, so future interrupts will be caught as desired. As a side effect to this change, OHCI_PARAM_DEBUG_BUSRESETS can now be enabled through sysfs in addition to during initial module loading. However, when enabled through sysfs, logging of bus reset interrupts will be effective only starting with the second bus reset, after bus_reset_work has executed.

References

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