CVE-2026-63883

Stale serial data disclosure via DMA race

Published Jul 19, 2026 · Updated Jul 19, 2026

Buffer underflow in the Qualcomm GENI serial driver allows local users to disclose or alter serial data through UART operations. After uart_flush_buffer() resets the transmit kfifo, handle_tx_dma() advances the empty queue by tx_remaining, wrapping its output index so the next DMA request reads stale contents. Triggering requires permission to open a Qualcomm GENI high-speed UART and race local write and flush operations; success exposes stale data and disrupts serial traffic.

CVSS severity7.3
High
EPSS probability0.17%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Buffer underflow in the Qualcomm GENI serial driver allows local users to disclose or alter serial data through UART operations. After uart_flush_buffer() resets the transmit kfifo, handle_tx_dma() advances the empty queue by tx_remaining, wrapping its output index so the next DMA request reads stale contents. Triggering requires permission to open a Qualcomm GENI high-speed UART and race local write and flush operations; success exposes stale data and disrupts serial traffic.

The record

CVE
CVE-2026-63883
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-124, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <0d2c41a8b00934ddf8a7c1b4cf72dffa1e629c46
  2. Affected versionversion=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <452d6fa37ae9b021f4f6d397dbae077f7296f6f4
  3. Affected versionversion=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <654f45a8569f3cd6ff20bd724a18e0cce65893ba
  4. Affected versionversion=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <b1159dce10b38eb795e4c96cdc4d34b83cec81c5
  5. Affected versionversion=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <c91ea13375f70f6271a0183445e34e83b8f4d8f7
  6. Affected versionversion=6.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <0d2c41a8b00934ddf8a7c1b4cf72dffa1e629c46; version=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <452d6fa37ae9b021f4f6d397dbae077f7296f6f4; version=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <654f45a8569f3cd6ff20bd724a18e0cce65893ba; version=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <b1159dce10b38eb795e4c96cdc4d34b83cec81c5; version=2aaa43c7077833301c237684cd7bc9ae5e3dec95 <c91ea13375f70f6271a0183445e34e83b8f4d8f7; version=6.3

Published CVSS scores

7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.3kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-124Buffer Underwrite ('Buffer Underflow')
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo