CVE-2026-93259

Boot failure via omitted r2 clobber

Published Sep 24, 2026 · Updated Sep 24, 2026

A register-clobber flaw in affected Linux kernels crashes PowerPC during interrupt handling and can prevent the kernel from booting. The call_do_irq and call_do_softirq inline assembly omits r2 from its clobber lists, so the compiler preserves live values in a caller-saved register that __do_irq or __do_softirq overwrites. The failure requires CONFIG_PPC_KERNEL_PCREL and compiler allocation of a live value to r2 across the stack-switching call.

CVSS severityUnavailable
Unscored
EPSS probability0.19%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A register-clobber flaw in affected Linux kernels crashes PowerPC during interrupt handling and can prevent the kernel from booting. The call_do_irq and call_do_softirq inline assembly omits r2 from its clobber lists, so the compiler preserves live values in a caller-saved register that __do_irq or __do_softirq overwrites. The failure requires CONFIG_PPC_KERNEL_PCREL and compiler allocation of a live value to r2 across the stack-switching call.

The record

CVE
CVE-2026-93259
Published
Sep 24, 2026
Updated
Sep 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 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=6.4
  2. Affected versionversion=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <00be69070d91d2be978e752bb117a0a4db0e1281
  3. Affected versionversion=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <602ee44415f3eaa7893f7fc488c7c1d4a0bdbd7a
  4. Affected versionversion=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <7b0093b638c8f2b94b0778a69fd1ccad54299b29
  5. Affected versionversion=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <90d953002cf0b233dd053a0e7cb67ab79cebd0e3
  6. Affected versionversion=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <dcc442a49c0f540193910dacdca7506bcadc7ec5

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.4; version=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <00be69070d91d2be978e752bb117a0a4db0e1281; version=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <602ee44415f3eaa7893f7fc488c7c1d4a0bdbd7a; version=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <7b0093b638c8f2b94b0778a69fd1ccad54299b29; version=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <90d953002cf0b233dd053a0e7cb67ab79cebd0e3; version=7e3a68be42e10f5fa5890e97afc0afd992355bc3 <dcc442a49c0f540193910dacdca7506bcadc7ec5

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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