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CVE-2026-74655

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CVE-2026-74655 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: serial: qcom-geni: fix TX DMA buffer flush When transmit flushing a qcom-geni UART during an ongoing TX DMA, the UART gets stuck infinitely repeating corrupted TX DMA frames. The DMA-mode uart_ops does not provide a flush_buffer callback, so an in-flight transfer can complete after serial core has reset the transmit kfifo, underflowing its length and resubmitting page-sized transfers indefinitely. Add one that stops the transfer and clears tx_remaining and tx_queued. The stop path was also broken: it unmapped the buffer while the serial engine could still read it, and never reset the TX DMA state machine. Cancel the main sequencer command first, then reset the state machine and wait for it before unmapping.

Description

In the Linux kernel, the following vulnerability has been resolved: serial: qcom-geni: fix TX DMA buffer flush When transmit flushing a qcom-geni UART during an ongoing TX DMA, the UART gets stuck infinitely repeating corrupted TX DMA frames. The DMA-mode uart_ops does not provide a flush_buffer callback, so an in-flight transfer can complete after serial core has reset the transmit kfifo, underflowing its length and resubmitting page-sized transfers indefinitely. Add one that stops the transfer and clears tx_remaining and tx_queued. The stop path was also broken: it unmapped the buffer while the serial engine could still read it, and never reset the TX DMA state machine. Cancel the main sequencer command first, then reset the state machine and wait for it before unmapping. Drop the early return so a pending mapping is also cleaned up when the main command is inactive. The bug can be triggered from userspace with a large write immediately followed by TCOFLUSH. A following tcdrain will hang forever. The bug was reproduced and this fix was validated on Arduino Uno Q (QRB2210) using /dev/ttyHS1.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 2aaa43c7077833301c237684cd7bc9ae5e3dec95, < 313ae287442e5e8d3f7b53b73f37d384bda072d0; >= 2aaa43c7077833301c237684cd7bc9ae5e3dec95, < 1c31e2377f4c1bb110ca7f6e597b2253a7440c37; >= 2aaa43c7077833301c237684cd7bc9ae5e3dec95, < b1801c0d40f62778b613334de5840aba10a564d5; >= 2aaa43c7077833301c237684cd7bc9ae5e3dec95, < e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d
LinuxLinux6.3

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74655?
In the Linux kernel, the following vulnerability has been resolved: serial: qcom-geni: fix TX DMA buffer flush When transmit flushing a qcom-geni UART during an ongoing TX DMA, the UART gets stuck infinitely repeating corrupted TX DMA frames. The DMA-mode uart_ops does not provide a flush_buffer callback, so an in-flight transfer can complete after serial core has reset the transmit kfifo, underflowing its length and resubmitting page-sized transfers indefinitely. Add one that stops the transfer and clears tx_remaining and tx_queued. The stop path was also broken: it unmapped the buffer while the serial engine could still read it, and never reset the TX DMA state machine. Cancel the main sequencer command first, then reset the state machine and wait for it before unmapping. Drop the early return so a pending mapping is also cleaned up when the main command is inactive. The bug can be triggered from userspace with a large write immediately followed by TCOFLUSH. A following tcdrain will hang forever. The bug was reproduced and this fix was validated on Arduino Uno Q (QRB2210) using /dev/ttyHS1.
How severe is CVE-2026-74655?
Severity scoring for CVE-2026-74655 is pending analysis.
How do I fix CVE-2026-74655?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST