EUVD-2026-64592
GHSA-fpvh-p63v-qp88
Severity by source
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Local PR:L trigger via UART device node write; S:C and C:H/I:H reflect DMA use-after-unmap kernel memory corruption potential; A:H confirmed by indefinite system hang.
Primary rating from Vendor (Linux).
CVSS VectorVendor: Linux
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
5DescriptionCVE.org
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.
AnalysisAI
TX DMA buffer mismanagement in the Linux kernel's Qualcomm GENI serial driver (qcom-geni) allows a local low-privileged user to hang the system indefinitely and potentially corrupt kernel memory on affected Qualcomm hardware. The driver's DMA-mode uart_ops lacks a flush_buffer callback, enabling in-flight DMA transfers to underflow the transmit kfifo and re-submit page-sized transfers indefinitely; a concurrent flaw in the stop path unmaps the DMA buffer while the serial engine is still reading it. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires local access to a Linux system running a vulnerable kernel version on Qualcomm hardware equipped with a GENI serial engine (e.g., QRB2210, Snapdragon-based boards). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score of 8.8 with vector AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H reflects a locally-exploitable kernel driver flaw with scope change to broader kernel memory impact. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A local user with read/write access to /dev/ttyHS1 on a Qualcomm QRB2210 or similar GENI-UART platform issues a large write to the UART device immediately followed by a TCOFLUSH (tcflush with TCOFLUSH). The missing flush_buffer callback allows the in-flight DMA to complete against the now-reset kfifo, underflowing its length counter and causing the kernel to endlessly re-queue page-sized DMA transfers; a subsequent tcdrain call hangs indefinitely, consuming kernel resources. … |
| Remediation | The fix is available in upstream Linux stable tree commits: 313ae287442e5e8d3f7b53b73f37d384bda072d0, 1c31e2377f4c1bb110ca7f6e597b2253a7440c37, b1801c0d40f62778b613334de5840aba10a564d5, and e3c04834ae1ab5e9cfbe8ac54ec734aa4774249d (see https://git.kernel.org/stable/c/ for each). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all systems running the Linux kernel on Qualcomm hardware, including embedded devices, IoT platforms, and mobile infrastructure. …
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