CVE-2026-74655
serial: qcom-geni: fix TX DMA buffer flush
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.
INFO
Published Date :
Aug. 22, 2026, 4:16 p.m.
Last Modified :
Aug. 22, 2026, 4:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-74655
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update the Linux kernel to the resolved version.
- Ensure TX DMA buffer flushing is handled correctly.
- Verify the stop path logic for TX DMA.
- Test the fix on affected hardware.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74655.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74655 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74655
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74655 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74655 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2aaa43c7077833301c237684cd7bc9ae5e3dec95', 'lessThan': '313ae287442e5e8d3f7b53b73f37d384bda072d0', 'versionType': 'git'}, {'status': 'affected', 'version': '2aaa43c7077833301c237684cd7bc9ae5e3dec95', 'lessThan': '1c31e2377f4c1bb110ca7f6e597b2253a7440c37', 'versionType': 'git'}, {'status': 'affected', 'version': '2aaa43c7077833301c237684cd7bc9ae5e3dec95', 'lessThan': 'b1801c0d40f62778b613334de5840aba10a564d5', 'versionType': 'git'}, {'status': 'affected', 'version': '2aaa43c7077833301c237684cd7bc9ae5e3dec95', 'lessThan': 'e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d', 'versionType': 'git'}], 'programFiles': ['drivers/tty/serial/qcom_geni_serial.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.3'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.3', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.104', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.45', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/tty/serial/qcom_geni_serial.c'], 'defaultStatus': 'affected'}] Added 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. Added Reference https://git.kernel.org/stable/c/1c31e2377f4c1bb110ca7f6e597b2253a7440c37 Added Reference https://git.kernel.org/stable/c/313ae287442e5e8d3f7b53b73f37d384bda072d0 Added Reference https://git.kernel.org/stable/c/b1801c0d40f62778b613334de5840aba10a564d5 Added Reference https://git.kernel.org/stable/c/e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d