CVE-2026-12629

Permanent hang via uncleared UART error interrupts

Published Aug 17, 2026 · Updated Aug 17, 2026

Denial of service in Zephyr RTOS before 4.4.2 allows physically proximate attackers to hang the system via crafted UART receive errors. In drivers/serial/uart_pl011.c, pl011_isr() handles PL011 receive error interrupts without writing the asserted error bits to UARTICR, so framing, parity, break, or overrun faults stay pending and immediately retrigger the ISR. Exposure is limited to PL011-based, interrupt-driven ports where software explicitly enables uart_irq_err_enable(); on those systems, a hostile serial peer can force an interrupt-storm livelock that leaves the core with no forward progress.

CVSS severity4.6
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 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

Denial of service in Zephyr RTOS before 4.4.2 allows physically proximate attackers to hang the system via crafted UART receive errors. In drivers/serial/uart_pl011.c, pl011_isr() handles PL011 receive error interrupts without writing the asserted error bits to UARTICR, so framing, parity, break, or overrun faults stay pending and immediately retrigger the ISR. Exposure is limited to PL011-based, interrupt-driven ports where software explicitly enables uart_irq_err_enable(); on those systems, a hostile serial peer can force an interrupt-storm livelock that leaves the core with no forward progress.

The record

CVE
CVE-2026-12629
Published
Aug 17, 2026
Updated
Aug 17, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-835, T1499
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 17, 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=1.14.0 <4.4.2

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=1.14.0 <4.4.2

Published CVSS scores

4.6GitHub Advisory DatabaseCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499Endpoint Denial of Service

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