CVE-2025-71132Network attack vector

System hang via unbalanced IRQ state

Published Jan 14, 2026 · Updated Jan 14, 2026

Affected Linux Kernel releases allow remote attackers to hang PREEMPT_RT systems by triggering smc91x network transmission. In smc91x.c, smc_special_trylock() disables interrupts, but smc_special_unlock() fails to restore them on PREEMPT_RT, leaving RCU state unbalanced during transmission. Exposure requires an SMP PREEMPT_RT kernel using the smc91x driver; repeated unauthenticated traffic can stall RCU grace periods and critical processing until the system hangs.

CVSS severity7.5
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Affected Linux Kernel releases allow remote attackers to hang PREEMPT_RT systems by triggering smc91x network transmission. In smc91x.c, smc_special_trylock() disables interrupts, but smc_special_unlock() fails to restore them on PREEMPT_RT, leaving RCU state unbalanced during transmission. Exposure requires an SMP PREEMPT_RT kernel using the smc91x driver; repeated unauthenticated traffic can stall RCU grace periods and critical processing until the system hangs.

The record

CVE
CVE-2025-71132
Published
Jan 14, 2026
Updated
Jan 14, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 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=342a93247e0837101f27bbcca26f402902df98dc <36561b86cb2501647662cfaf91286dd6973804a6
  2. Affected versionversion=342a93247e0837101f27bbcca26f402902df98dc <6402078bd9d1ed46e79465e1faaa42e3458f8a33
  3. Affected versionversion=342a93247e0837101f27bbcca26f402902df98dc <9d222141b00156509d67d80c771fbefa92c43ace
  4. Affected versionversion=342a93247e0837101f27bbcca26f402902df98dc <b6018d5c1a8f09d5efe4d6961d7ee45fdf3a7ce3
  5. Affected versionversion=342a93247e0837101f27bbcca26f402902df98dc <ef277ae121b3249c99994652210a326b52d527b0
  6. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=342a93247e0837101f27bbcca26f402902df98dc <36561b86cb2501647662cfaf91286dd6973804a6; version=342a93247e0837101f27bbcca26f402902df98dc <6402078bd9d1ed46e79465e1faaa42e3458f8a33; version=342a93247e0837101f27bbcca26f402902df98dc <9d222141b00156509d67d80c771fbefa92c43ace; version=342a93247e0837101f27bbcca26f402902df98dc <b6018d5c1a8f09d5efe4d6961d7ee45fdf3a7ce3; version=342a93247e0837101f27bbcca26f402902df98dc <ef277ae121b3249c99994652210a326b52d527b0; version=5.15

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5kernel.orgCVSS:3.1/AV:N/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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

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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