CVE-2026-74653

Local CPU livelock via uncleared RX timeout

Published Aug 22, 2026 · Updated Aug 25, 2026

Denial of service in Linux 2.6.36 through 6.18.44 and 7.0 through 7.1.8 allows local users to livelock LPC32xx systems. On an empty-FIFO RX timeout, serial8250_rx_chars() skips the RHR read required to clear the level-triggered interrupt because LSR.DR is unset. The behavior requires an NXP LPC32xx UART driven by generic 8250_of on a single-core ARM926; the interrupt storm causes a CPU soft lockup.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux 2.6.36 through 6.18.44 and 7.0 through 7.1.8 allows local users to livelock LPC32xx systems. On an empty-FIFO RX timeout, serial8250_rx_chars() skips the RHR read required to clear the level-triggered interrupt because LSR.DR is unset. The behavior requires an NXP LPC32xx UART driven by generic 8250_of on a single-core ARM926; the interrupt storm causes a CPU soft lockup.

The record

CVE
CVE-2026-74653
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-835, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=2.6.36
  2. Affected versionversion=e6e912c4964ce5976e508881207dfa96d5f856d7 <1423415471274abda87024967d7fe2206ceee0ea
  3. Affected versionversion=e6e912c4964ce5976e508881207dfa96d5f856d7 <3ce24bc4d115336218e59b7e286fd3a79f4fc4c6
  4. Affected versionversion=e6e912c4964ce5976e508881207dfa96d5f856d7 <7795e8abedc86438cae0454602cbf9038b94bf38

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.36; version=e6e912c4964ce5976e508881207dfa96d5f856d7 <1423415471274abda87024967d7fe2206ceee0ea; version=e6e912c4964ce5976e508881207dfa96d5f856d7 <3ce24bc4d115336218e59b7e286fd3a79f4fc4c6; version=e6e912c4964ce5976e508881207dfa96d5f856d7 <7795e8abedc86438cae0454602cbf9038b94bf38

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
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.

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Technologies

Your stack

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Your stack

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